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Biomedical subjects

M Grond

Publications and source records attributed to M Grond.

At least 19 recordsLinked to original sources
PubMed2006

[Guidelines given by the DSG and DGN concerning stroke therapy--new therapeutic aspects].

Surgeries of symptomatic carotid stenose should not be operated on later than 14 days after stroke; until the operation inhibitors of platelet aggregation have to be administered (Table 1). The application of anticoagulants like warfarin or phenprocoumon in case of intracranial stenoses is no longer recommended. Instead 100-300 mg aspirin should prophylactically be given. The risk of suffering a stroke is significantly reduced by the application of antihypertensives. Patients with focal cerebral ischemia should be given 40 mg of Simvastatin which leads to a significant decrease of vascular risk. After the first cerebral ischemic incidenz patients with open foramen ovale of the heart should be given 100-300 mg aspirin. In case of aspirin relapse an oral anticoagulation has to be carried out with an INR of 2.0 up to 3 for at least one year.

Aged↗
PubMed2003

[Brainstem edema during a hypertensive crisis with vasogenic and cytotoxic concerns].

HISTORY AND ADMISSION FINDINGS: A 66-year-old woman on antihypertensive treatment was urgently admitted to a neurological/neuroradiological unit with signs of a mild brainstem syndrome and possible hypertensive crisis. INVESTIGATIONS: Magnetic resonance imaging (MRI) of the head indicated both intracellular (so-called cytotoxic) and vasogenic edema. TREATMENT AND COURSE: After antihypertensive medication all symptoms disappeared within an hour and the MRI became essentially normal. CONCLUSION: The reversible vasogenic edema was probably caused by an hypertensive encephalopathy, while the signs of focal cerebral ischemia were due to an intracellular, ultimately irreversible, edema. In this case there was evidence of both phenomena having occurred concomitantly.

Aged↗
PubMed2003

Acute stroke treatment in Europe: a questionnaire-based survey on behalf of the EFNS Task Force on acute neurological stroke care.

In 1997 the EFNS Task Force on Acute Neurological Stroke Care published its recommendations for acute stroke care (Brainin et al., 1997), which, in 1999, was followed by a stroke care inventory (Brainin et al., 2000) assessing the development of acute stroke care. In 2000 all 33 members of the EFNS Stroke Scientist Panel were asked to complete a questionnaire on the treatment of acute stroke in their country as of 2000. Data were based either on national surveys or a personal estimate of national practice, together with data from the personal practice of the panel member. Data from 22 countries were received. One of the principal findings is the lack of systematic evidence about practice in a significant number of European countries. Results illustrate that neurologists have a leading role in implementing acute stroke treatment guidelines and in adopting new therapeutic methods in most countries, but there is a wide variation in the application of different therapeutic procedures.

Advisory Committees↗
PubMed2002

Feasibility of source images of computed tomographic angiography to detect the extent of ischemia in hyperacute stroke.

BACKGROUND AND PURPOSE: Computed tomographic angiography (CTA) is suggested to be a promising tool for patient selection for thrombolytic therapy of acute stroke. It does not only provide information on intracranial vasculature, but also on the capacity of the collateral circulation and the pattern of poorly perfused brain tissue. The objective of our study was to evaluate whether the presence and size of critically hypoperfused tissue assessed with flow positron emission tomography (PET) as a gold standard can reliably be identified on CTA source images. METHODS: Fifteen potential candidates for early thrombolysis underwent CTA 65-170 min (mean 107 min) after the onset of acute anterior circulation stroke. Regional cerebral perfusion was measured between 27 and 86 min (mean 59 min) later with [(15)O]-H(2)O and PET, and the volume of critically hypoperfused cortical tissue was assessed. CTA source images were evaluated by a neuroradiologist and an experienced stroke neurologist. The patients were classified into three groups according to the presumed size of the perfusion deficit on CTA (large, small, no perfusion deficit). RESULTS: PET revealed the presence of critical cortical hypoperfusion in 10 patients, 5 had no critical cortical hypoperfusion. The neuroradiologist correctly identified the presence of a perfusion deficit in all patients, the neurologist had two false negative and one false positive ratings. Concerning the size of the perfusion deficit, there was considerable inaccuracy in both raters. CONCLUSIONS: The usefulness of CTA source images in yielding information about the perfusion state of stroke patients in clinical routine should not be overestimated.

Adult↗
PubMed2001

Predictors of good outcome after intravenous tPA for acute ischemic stroke.

BACKGROUND: Thrombolytic therapy for acute ischemic stroke with IV alteplase is increasingly well established in North America but not elsewhere. Baseline factors that altered the response to alteplase were not identified by the National Institute of Neurological Disorders and Stroke tPA Stroke Study Group. METHODS: The authors gathered information from centers in the United States, Canada, and Germany on 1,205 patients with acute ischemic stroke treated with IV alteplase. The purpose was to identify independent factors that were predictive of good outcome using multivariable logistic regression modelling. The modified Rankin Scale score was dichotomized into good outcome (mRS 0 to 1) and poor outcome (mRS >1) as the primary outcome measure. RESULTS: In relative order of decreasing magnitude, milder baseline stroke severity, no history of diabetes mellitus, normal CT scan, normal pretreatment blood glucose level, and normal pretreatment blood pressure were independent predictors of good outcome among patients treated with IV alteplase for acute ischemic stroke. Confounding was observed among history of diabetes mellitus, CT scan appearance, baseline serum glucose level, and blood pressure, suggesting important relationships among these variables. CONCLUSIONS: Several factors were independently predictive of good outcome among patients with acute ischemic stroke treated with alteplase. These results require further confirmation before clinical implementation.

Acute Disease↗
PubMed2001

Elevation of extracellular glutamate in the final, ischemic stage of progressive epidural mass lesion in cats.

Epidural mass lesions may cause ischemia due to progressive intracranial hypertension. In order to investigate the impact of intracranial pressure on accumulation of neuroactive substances, we gradually raised intracranial pressure in five halothane anesthetized cats by inflation of an epidural balloon. We evaluated in the parietal cortex contralateral to the site of balloon inflation, alterations of extracellular glutamate and purine catabolites and of the lactate/pyruvate ratio in relation to changes of intracranial, cerebral perfusion and mean arterial blood pressure. In a complementary experiment, regional cerebral blood flow was assessed by sequential positron emission tomography. In this simplified mass lesion model, extracellular glutamate increased in all cats at a late, critical stage after tentorial herniation, when intracranial pressure had increased to more than 90 mm Hg, cerebral perfusion pressure had decreased below 40-50 mm Hg. Positron emission tomography assessments revealed that the ischemic threshold for glutamate accumulation was in the range of 15-20 mL/100 g/min. Purine catabolites and the lactate/pyruvate ratio increased somewhat earlier than glutamate, but also after reaching the critical, terminal stage. We conclude that in this model of progressive epidural compression, glutamate-mediated excitotoxic processes at sites remote from the initial focal lesion depend on processes such as delayed ischemia in combination with tentorial herniation and systemic hypotension. These processes seem to be initiated by a decrease of cerebral perfusion pressure below a threshold of 40-50 mm Hg.

Animals↗
PubMed2001

Penumbral probability thresholds of cortical flumazenil binding and blood flow predicting tissue outcome in patients with cerebral ischaemia.

Active treatment of acute ischaemic stroke can only be successful as long as tissue in the area of ischaemic compromise is still viable. Therefore, the identification of the area of irreversible damage, and its distinction from the penumbral zone, may improve the estimation of the potential efficacy of various therapeutic strategies. Ten patients (seven male, three female, aged 52-75 years) with acute ischaemic stroke, in whom MRI delineated an infarct involving the cortex 3 weeks after the attack, were studied by [(11)C]flumazenil (FMZ) PET to assess their neuronal integrity, and regional cerebral blood flow (CBF) was measured by H(2)(15)O PET 2-12 h (median interval 6 h) after onset of symptoms. Cortical volumes of interest (3 mm radius) were placed on co-registered CBF, FMZ and on late MRI scans. Using initial CBF and FMZ binding data from volumes of interest finally located within or outside the cortical infarct, cumulative probability curves were computed to predict eventual infarction or non-infarction. Positive (at least 95% chance of infarct) and negative (at least 95% chance of non-infarct) prediction limits for CBF (4.8 and 14.1 ml/100 g/min, respectively) and for FMZ binding (3.4 and 5.5 times the mean of normal white matter, respectively) were determined to define the penumbral range. Using the lower FMZ binding threshold of 3.4 for irreversible tissue damage and the upper CBF value of 14.1 ml/ 100 g/min for the threshold of critical perfusion at or above which tissue will likely be preserved, various cortical subcompartments were identified: of the final cortical infarct (median size 25.7 cm(3)) a major portion comprising, on average, 55.1% showed FMZ binding critically decreased, thus predicting necrosis. In 20.5% of the final infarct, on average, CBF was in the penumbral range (<14.1 ml/100 g/min) and FMZ binding was above the critical threshold of irreversible damage. Only 12.9% of the final infarct exhibited neuronal integrity and CBF values above the penumbral range. Therefore, most of the final infarct is irreversibly damaged already at the time of the initial evaluation, when studied several hours after stroke onset. A much smaller portion is still viable but suffers from insufficient blood supply: this tissue may be salvaged by effective reperfusion. Only an even smaller compartment is viable and sufficiently perfused, but eventually becomes necrotic, mainly owing to delayed mechanisms, and may benefit from neuroprotective or other measures targeted at secondary damage. Therefore, early reperfusion is crucial in acute ischaemic stroke.

Aged↗
PubMed2001

Intravenous thrombolysis in proximal middle cerebral artery occlusion.

Subgroup analyses of data from an open-label study of intravenous recombinant tissue plasminogen activator (rt-PA) administered to stroke patients were performed. Clinical outcome and incidence of intracranial hemorrhage were evaluated in 20 patients diagnosed by transcranial Doppler ultrasound as having proximal middle cerebral artery (MCA) occlusion. Additionally early infarct signs and size of final infarction were assessed. A favorable outcome (mRS 0-2) was seen in 30% of all patients. The incidence of symptomatic intracranial hematoma (10%) in patients with proximal MCA occlusion was higher than the overall hemorrhage rate of intravenous rt-PA treatment, but comparable to the data on intra-arterial thrombolysis in this stroke subgroup. All patients except 1 developed ischemic infarction in the MCA territory. Intravenous rt-PA treatment within 3 h may also be effective in patients with proximal MCA occlusion. The risk of intracerebral hematoma does not seem to be greater than in intra-arterial thrombolysis.

Aged↗
PubMed2001

Predictive value of neurochemical monitoring in large middle cerebral artery infarction.

BACKGROUND AND PURPOSE: Space-occupying brain edema is a life-threatening complication in patients with large hemispheric stroke. Early identification of patients at risk is necessary to decide on invasive therapies such as decompressive hemicraniectomy or hypothermia. To assess potential predictors of malignant brain edema by measurement of intracranial pressure (ICP) and microdialysis in patients with large hemispheric stroke and different clinical course. METHODS: In an ongoing prospective clinical study, an ICP and microdialysis probe were placed into the parenchyma of the ipsilateral frontal lobe of 10 patients. Extracellular concentrations of glutamate, lactate, pyruvate, and glycerol were measured continuously. Repeated cranial CT scans were scrutinized for size of infarction and presence of mass effect. RESULTS: The dynamics of the different substances varied in accordance with the clinical course, size of infarction, and local brain edema: Increase in ICP and in glutamate concentration and lactate-pyruvate ratio was followed by massive edema and large infarcts; generally low and stable ICP and substrate concentrations were found in patients without progressive space-occupying infarcts. CONCLUSIONS: In patients with large hemispheric infarction, bedside monitoring with microdialysis is feasible and might be helpful together with ICP recording to follow the development of malignant brain edema.

Adult↗