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Biomedical subjects

H B van der Worp

Publications and source records attributed to H B van der Worp.

At least 19 recordsLinked to original sources
PubMed2006

Anatomic variations in the circle of Willis in patients with symptomatic carotid artery stenosis assessed with multidetector row CT angiography.

PURPOSE: To assess the presence of anterior and posterior collateral pathways in the circle of Willis in patients with symptomatic carotid artery stenosis (SCAS) and to compare this to patients without carotid artery stenosis. MATERIALS AND METHODS: Multislice CT angiography was performed in 91 patients and 91 control subjects. Using consensus reading, 2 observers evaluated the presence and diameter of the anterior communicating artery (AcomA), the A1 segments of the anterior cerebral arteries, the posterior communicating arteries (PcomA) and the P1 segments of the posterior cerebral arteries. Anterior or posterior pathways were assumed to be present if the diameter of continuous arterial segments was >1 mm; both A1 segments and AcomA anterior, and ipsilateral P1 segment and PcomA posterior. Comparison between patients and controls was performed using the chi(2) test. RESULTS: In the patients we found significantly more hypoplastic (<1 mm) or invisible A1 segments (16 and 14 vs. 4 and 1, respectively, p < 0.01). The AcomA was invisible in 4 patients versus 1 control. An isolated compromised anterior pathway and a combined compromised anterior and posterior pathway occurred more frequently in the patients as compared to the controls; 9 versus 1% (p < 0.01) and 26 versus 4% (p < 0.01). CONCLUSION: A compromised anterior collateral pathway, usually combined with a compromised posterior pathway, occurs more frequently in patients with SCAS as compared to controls, which suggests a relation between symptomatic carotid stenosis and an incomplete circle of Willis.

Adult↗
PubMed2006

[Stenting of symptomatic stenosis of the internal carotid artery is not preferred over endarterectomy at this time].

Carotid endarterectomy reduces the risk of stroke in patients with symptomatic internal carotid-artery stenosis of 50% or greater. Carotid-artery stenting may be an attractive alternative. Two randomised trials comparing carotid endarterectomy with stenting have recently been terminated prematurely. Reasons for termination included an excess in stroke and death after stenting, compared with carotid endarterectomy (the EVA-3S trial) and futility reasons and the absence of funding (the SPACE trial). Given that both trials failed to prove the non-inferiority of stenting compared with carotid endarterectomy in the first 30 days, the use of stenting should be restricted to patients with contraindications to surgery and those participating in randomised clinical trials.

Carotid Artery, Internal↗
PubMed2006

Early cognitive impairment predicts long-term depressive symptoms and quality of life after stroke.

OBJECTIVE: The aim of the present study was to examine the predictive value of cognitive impairment in the acute phase after stroke as a risk factor for long-term (six to ten months after stroke) depressive symptoms (DS) and a reduced quality of life (QOL), independent of demographic and neurological predictors. METHODS: We evaluated 143 patients within the first 3 weeks post-stroke. Predictor variables included domain-specific cognitive function, demographic data, vascular risk factors, lesion characteristics, and clinical factors. Predictor variables associated with long-term DS (Montgomery Asberg Depression Rating Scale >or=7) and QOL (Stroke-Specific Quality of Life Scale) were identified with multiple logistic and linear regression. RESULTS: Long-term DS were independently predicted by cognitive impairment at baseline, DS at baseline, female sex, diabetes mellitus, and previous TIA(s). Cognitive impairment, increasing age, and functional dependence predicted a reduced QOL, whereas hypercholesterolaemia predicted a better QOL. Among all cognitive disorders, unilateral neglect was the greatest risk factor for DS after 6 months, whereas a disorder in visual perception and construction affected QOL the most. CONCLUSIONS: Cognitive impairment and vascular risk factors are important predictors of long-term DS and QOL after stroke. The prognostic value of cognition suggests a reactive component in the development or continuation of long-term DS.

Aged↗
PubMed2006

Neuropsychological and neuroanatomical correlates of perseverative responses in subacute stroke.

Patients with left-sided neglect frequently show repetitive behaviour on the ipsilesional side, such as re-markings on cancellation tasks or extensive elaboration on drawings. It is unclear whether these perseverative responses occur as a symptom of hemi-neglect or inattention in general, and/or whether they are related to anatomical brain correlates such as lesion location, lesion side or volume. In a first study, we examined the prevalence and neuropsychological correlates of perseverative responses in 206 subacute stroke patients and 63 healthy controls. Perseverative responses were considered present when there was at least one re-marking on the Star Cancellation, and both the degree and spatial distribution of re-markings were examined. A distinction was made between hemi-neglect and non-lateralized inattention. Spatial and verbal working memory were assessed with the Corsi Block Span and the Digit Span. Verbal and non-verbal executive function was assessed with the Visual Elevator and Letter Fluency. Stroke patients without inattention demonstrated re-markings that were related to executive performance, and the degree of perseveration was equally distributed across the sheet. Hemi-neglect patients but not patients with generalized inattention demonstrated more re-markings than controls, suggesting that a lateralized spatial attention bias triggers the perseverative responses. Patients with left and right hemi-neglect showed the same prevalence of perseveration, but the distribution of re-markings was more lateralized towards the ipsilesional side in patients with right-hemispheric stroke. The degree of perseveration in patients with hemi-neglect was related to the severity of the neglect. The goal of the second study on a subset of patients (n = 127) was to determine the neuroanatomical correlates of perseverative responses in the early phase of stroke. Lesion anatomy was administered by indicating involvement of frontal, parietal, temporal, occipital lobe, caudate nucleus, lenticular nucleus and/or thalamus. Lesion volume was calculated using a manual tracing technique. Lesion analyses indicated that perseverative behaviour is strongly associated with lesions involving the caudate nucleus or the lenticular nucleus, independent of lesion volume. The caudate nucleus was an important correlate of perseveration independent of the presence of hemi-neglect. No association was found between lesion side and perseverative responses, in contrast to previous studies. In conclusion, a stroke involving the basal ganglia and the presence of (left- or right-sided) hemi-neglect are two important associates of perseverative responses in the subacute phase of stroke.

Acute Disease↗
PubMed2005

The prognostic value of domain-specific cognitive abilities in acute first-ever stroke.

OBJECTIVE: To evaluate the prognostic value of domain-specific cognitive abilities in acute stroke with respect to long-term cognitive and functional outcome in addition to neurologic and demographic predictors. METHODS: The authors evaluated 168 patients within the first 3 weeks after first-ever stroke. The prevalence of neuropsychological impairment was calculated vs 75 matched healthy controls. The authors also recorded demographic data, vascular risk factors, lesion characteristics, and clinical factors at admission. Independent predictor variables associated with long-term cognitive impairment (assessed with a follow-up neuropsychological examination) and functional impairment (assessed with the modified Barthel Index and the Frenchay Activities Index) were identified with stepwise multiple logistic regression. Areas under receiver operator characteristic curves were used to compare the predictive value of three models, i.e., a standard medical model, a purely cognitive model, and a model consisting of both medical and cognitive predictors. RESULTS: Thirty-one percent of patients showed long-term cognitive impairment. Basic and instrumental ADL disturbances remained present in 19% and 24% of patients. Domain-specific cognitive functioning predicted cognitive and functional outcome better than any other variable. Moreover, the prediction of instrumental ADL functioning improved when cognitive predictors were added to the standard medical model (p < 0.05). Impairments in abstract reasoning and executive functioning were independent predictors of long-term cognitive impairment. Inattention and perceptual disorders were more important in predicting long-term functional impairment. CONCLUSION: Domain-specific cognitive abilities in the early phase of stroke are excellent independent predictors of long-term cognitive and functional outcome.

Acute Disease↗
PubMed2005

Early depressive symptoms after stroke: neuropsychological correlates and lesion characteristics.

OBJECTIVE: To examine the relation between depressive symptoms and specific cognitive functions in patients with a recent stroke and to examine associations with lesion characteristics. METHODS: We studied 126 of 183 consecutive patients within 3 weeks after a first-ever symptomatic stroke (mean interval, 8.3+/-4.3 days). Presence and severity of depressive symptoms was assessed with the Montgomery Asberg Depression Rating Scale. Neuropsychological functioning was examined by means of a detailed neuropsychological examination covering six cognitive domains. We included a healthy control group (N=75) to obtain normative data for the neuropsychological examination. Functional impairment was measured with the modified Barthel Index and the modified Rankin Scale. Symptomatic and preexistent lesion characteristics were determined on CT or MRI. RESULTS: Of the included patients, 40% demonstrated mild and 12% moderate to severe depressive symptoms. Severity of depressive symptoms was related to lesion volume (p=0.008), functional impairment (all p<0.004), and degree of overall cognitive impairment (p=0.005). After adjustment for lesion size, a specific neuropsychological profile emerged in patients with moderate to severe depressive symptoms, affecting primarily memory, visual perception, and language (all p<0.05). No association was found between severity of depressive symptoms and lesion location, presence of preexistent lesions (white matter lesions and silent infarcts), and demographic factors (age, education, and gender). CONCLUSIONS: Moderate or severe symptoms of depression in the early stage poststroke are associated with a specific pattern of cognitive impairment, lesion size, and functional status. We suggest that depressive symptoms early after stroke are, at least in part, a reactive phenomenon secondary to severe cognitive and functional deficits.

Aged↗
PubMed2005

Comparison of perfusion MRI by flow-sensitive alternating inversion recovery and dynamic susceptibility contrast in rats with permanent middle cerebral artery occlusion.

We compared cerebral blood flow (CBF) parameters obtained by dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) with those obtained by flow-sensitive alternating inversion recovery (FAIR) in brain regions with different perfusion levels in rats with permanent middle cerebral artery (MCA) occlusion. MCA occlusion was performed in 19 rats. T2-weighted MRI, FAIR and DSC-MRI were performed within 48 h after occlusion. CBF parameters were analyzed in regions of interest with either prolonged or less prolonged mean transit time (MTT). Ratios of ipsi- vs contralateral CBF values were calculated and tested for correlation and differences between FAIR and DSC-MRI. FAIR-aCBF ratios correlated significantly with DSC-rCBF ratios. The mean FAIR-aCBF ratio was significantly lower than mean DSC-rCBF ratio in the area with prolonged MTT. In the area with less prolonged MTT, the mean FAIR-aCBF ratio and mean DSC-rCBF values did not differ significantly. We conclude that FAIR correlates with DSC-MRI if perfusion is preserved. FAIR provides lower CBF values than DSC-MRI if perfusion is reduced and MTT is prolonged. This probable underestimation of perfusion may be caused by transit delays. Care should be taken when quantifying CBF with FAIR and when comparing the results of FAIR- and DSC-MRI in areas with hypoperfusion.

Animals↗
PubMed2005

Applicability and relevance of models that predict short term outcome after intracerebral haemorrhage.

OBJECTIVES: Several models for prediction of short term outcome after intracerebral haemorrhage (ICH) have been published, however, these are rarely used in clinical practice for treatment decisions. This study was conducted to identify current models for prediction of short term outcome after ICH and to evaluate their clinical applicability and relevance in treatment decisions. METHODS: MEDLINE was searched from 1966 to June 2003 and studies were included if they met predefined criteria. Regression coefficients of multivariate models were extracted. Two neurologists independently evaluated the models for applicability in clinical practice. To assess clinical relevance and accuracy of each model, in a validation series of 122 patients the proportion with a >or=95% probability of death or poor outcome and the actual 30 day case fatality in these patients were calculated. Receiver operator characteristic (ROC) curves were computed for assessment of discriminatory power. RESULTS: A total of 18 prognostic models were identified, of which 14 appeared easy to apply. In the validation series, the proportion of patients with a >or=95% probability of death or poor outcome ranged from 0% to 43% (median 23%). The 30 day case fatality in these patients ranged from 75% to 100% (median 93%). The area under the ROC curves ranged from 0.81 to 0.90. CONCLUSIONS: Most models are easy to apply and can generate a high probability of death or poor outcome. However, only a small proportion of patients have such a high probability, and 30 day case fatality is not always correctly predicted. Therefore, current models have limited relevance in triage, but can be used to estimate the chances of survival of individual patients.

Adolescent↗
PubMed2004

The time course of ischemic damage and cerebral perfusion in a rat model of space-occupying cerebral infarction.

We aimed to establish a rat model of space-occupying hemispheric infarction to evaluate potential treatment strategies. For adequate timing of therapy in future experiments, we studied the development of tissue damage, edema formation, and perfusion over time with different MRI techniques. Permanent middle cerebral artery (MCA) occlusion was performed in 32 Fisher-344 rats. Forty-six MRI experiments including diffusion weighted (DW), T2-weighted (T2W), flow-sensitive alternating inversion recovery (FAIR) perfusion-weighted, and T1-weighted (T1W) imaging before and after gadolinium were performed at 1, 3, 8, 16, 24, and 48 h of ischemia. MCA occlusion consistently led to infarction of the complete MCA territory. Mortality was 75%. Lesion volumes as derived from apparent diffusion coefficient (ADC) and T2 maps increased to maximum values of 400+/-48 mm3 at 24 h and 420+/-54 mm3 at 48 h of ischemia, respectively. Midline shift peaked at 24 h. The area with diffusion-perfusion deficit decreased to a minimum at 24 h after onset of ischemia and perfusion of the contralateral hemisphere dropped at the same time point. Leakage of gadolinium through the blood-brain barrier in the entire infarct occurred within 3 h of ischemia. Permanent intraluminal MCA occlusion in Fisher-344 rats is an adequate model for space-occupying cerebral infarction. Rats may benefit from intervention aimed at reducing tissue shift and intracranial pressure (ICP), and at improving cerebral blood flow, if initiated before 24 h after MCA occlusion. The value of treatment modalities depending on an intact blood-brain barrier should be questioned.

Animals↗
PubMed2004

Delayed decompressive surgery increases apparent diffusion coefficient and improves peri-infarct perfusion in rats with space-occupying cerebral infarction.

BACKGROUND AND PURPOSE: There is no conclusive experimental support that decompressive surgery in late stages of space-occupying cerebral infarction will improve outcome. We studied the effects of delayed decompressive surgery on the development of tissue damage, edema formation, and cerebral perfusion with different MRI techniques in a rat model of space-occupying cerebral infarction. METHODS: Permanent middle cerebral artery (MCA) occlusion was performed in 6 Fisher 344 rats. Decompressive surgery was performed 17 hours after the occlusion. Each animal was assessed before surgery and 2 and 4 hours after surgery by means, of diffusion-weighted T2-weighted, and flow-sensitive alternating inversion recovery perfusion-weighted MRI. Ischemic damage was also evaluated in hematoxylin-eosin-stained brain sections. RESULTS: Lesion volume as derived from apparent diffusion coefficient (ADC) maps decreased from 522+/-98 mm3 before to 405+/-100 mm3 (P=0.016) 4 hours after decompressive surgery, whereas lesion volume from T2 maps increased from 420+/-66 mm3 before to 510+/-92 mm3 (P=0.048) 4 hours after decompressive surgery. Midline shift decreased from 1.4+/-0.1 mm to 0.5+/-0.2 mm (P=0.001). Blood flow in the noninfarcted area of the ipsilateral hemisphere improved from 25+/-9 mL/min/100 g of tissue to 38+/-9 mL/min/100 g of tissue (P=0.035). Despite the pseudonormalization of ADC, irreversible damage was found in the entire MCA territory on histological evaluation. CONCLUSIONS: In rats with space-occupying cerebral infarction, delayed decompressive surgery leads to a decrease in lesion volume derived from ADC maps, which is probably because of an increase of extracellular water formation. There are no signs that this reflects rescue of ischemic tissue.

Animals↗
PubMed2004

[Prevention of cardiovascular complications after a stroke or TIA: hypotensive and hypocholesterolemic therapy].

In patients who have recently had a TIA or stroke, the risk of new serious cardiovascular disease is decreased by the pharmacological reduction of the serum cholesterol level and blood pressure; this has been convincingly demonstrated by randomised clinical trials. There is sufficient evidence that cholesterol-lowering treatment is effective in patients with a TIA or cerebral infarction who have a total cholesterol > or = 3.5 mmol/l. The results from a trial in patients with only a TIA or a minor stroke will have to answer the question whether cholesterol-lowering treatment will be effective in patients > 80 years, and whether higher dosages of simvastatin will be more effective in these patients. Antihypertensive therapy is effective in preventing recurrent stroke and myocardial infarction in patients with a recent stroke or TIA. It is obvious that the treatment should be started with a diuretic and that a second agent should be added if necessary. On epidemiological grounds, vigorous treatment is also justified in patients with a normal or mildly elevated blood pressure; caution and a custom-tailored approach are essential, however, in each individual patient.

Anticholesteremic Agents↗
PubMed2004

[Treatment of optic neuritis].

Optic neuritis manifests itself as a reversible loss of vision. It can be a clinically isolated incident or one of the (first) manifestations of multiple sclerosis (MS). Its differential diagnosis is extensive, and management of other disorders can differ radically. In a typical case, treatment with corticosteroids hastens recovery of vision but does not affect the eventual degree of recovery. There is a substantial risk of developing MS after isolated optic neuritis (approximately 50% within 20 years), especially if asymptomatic white matter lesions are found on MRI scanning of the brain. Intravenous treatment with methylprednisolone may delay the onset of MS somewhat, but after three years the benefit of this treatment is lost. Treatment with interferon beta-Ia in high-risk patients also slows down the progression to clinically definite MS, but the long-term benefits are uncertain. MR imaging of the brain has implications for prognosis but not for treatment.

Brain↗
PubMed2003

[Surgical decompression in space-occupying cerebral infarct; notification of a randomized trial].

Patients with a hemispheric infarct and massive space-occupying brain oedema have a poor prognosis. Despite intensive conservative treatment, the case fatality rate may be as high as 80%, and most survivors are left severely disabled. Non-randomised studies suggest that decompressive surgery substantially reduces mortality and improves the functional outcome of survivors. The 'Hemicraniectomy after middle cerebral artery infarction with life-threatening edema trial' (HAMLET) is a newly-conceived randomised multi-centre clinical trial that compares the efficacy of decompressive surgery to improve functional outcome with that of conservative treatment in patients with space-occupying supratentorial infarction.

Brain↗
PubMed2003

[Treatment of stroke by reducing the body temperature; 'Paracetamol (acetaminophen) in stroke' (PAIS): start of a clinical trial].

Subfebrile temperatures and fever in acute stroke are associated with poor functional outcome. A 1 degree C rise in body temperature may double the risk of a poor outcome in patients who are admitted within 12 hours from the onset of symptoms. Two randomised double-blind clinical trials in patients with acute ischaemic stroke have shown that treatment with a daily dose of 6 g paracetamol results in a small but rapid and potentially worthwhile reduction of 0.3 degree C (95% CI: 0.1-0.5) in body temperature. It has been hypothesized that early antipyretic therapy reduces the risk of death or dependency in patients with acute stroke, even if they are normothermic. For this reason, a multicentre, randomized, double-blind clinical trial comparing high-dose paracetamol with placebo in 2500 patients has been launched. This study has been named 'Paracetamol (acetaminophen) in stroke' (PAIS). The primary outcome is death or dependency at three months. The study protocol is simple, and the amount of data to be gathered is limited. The trial will run for four years.

Acetaminophen↗
PubMed2003

Timing of the effect of acetaminophen on body temperature in patients with acute ischemic stroke.

The authors assessed the time of onset of the hypothermic effect of acetaminophen in 102 patients with acute ischemic stroke. These patients were randomized to treatment with either 1000 mg of acetaminophen (n = 52) or placebo (n = 50), given six times daily. Treatment with high-dose acetaminophen resulted in a 0.26 degrees C (95% CI 0.07 to 0.46 degrees C) lower mean body temperature than placebo treatment within 4 hours. This effect remained present throughout the next 20 hours. A large phase III trial seems warranted.

Acetaminophen↗
PubMed2002

The effect of tirilazad mesylate on infarct volume of patients with acute ischemic stroke.

The authors investigated whether the lack of effect of tirilazad on clinical outcome in patients with acute ischemic stroke is explained by failure of tirilazad to reduce infarct volume. Overall, tirilazad had no significant effect on infarct volume. In the subgroups of male patients and of those with a cortical infarct, tirilazad significantly reduced infarct volume. These effects were reduced to nonsignificant trends after adjustment for imbalances in baseline characteristics. In conclusion, early treatment of patients with tirilazad has no effect on infarct volume.

Aged↗
PubMed2001

Reproducibility of measurements of cerebral infarct volume on CT scans.

BACKGROUND AND PURPOSE: Infarct volume is increasingly used as an outcome measure in clinical trials of therapies for acute ischemic stroke. We tested which of 5 different methods to measure infarct size or volume on CT scans has the highest reproducibility. METHODS: Infarct volume and total intracranial volume were measured with Leica Q500 MCP image analysis software, or with a caliper, on 38 CT scans of patients who participated in the Tirilazad Efficacy Stroke Study II (TESS II). The scans were performed 8 days (+/-2 days) after the onset of symptoms. The 5 methods tested were based on (1) semiautomated pixel thresholding, (2) manual tracing of the perimeter, (3) a stereological counting grid, (4) measurement of the 3 largest diameters, and (5) the single largest diameter. The measurements were performed independently by 2 observers; the first observer performed all measurements twice. RESULTS: The single largest diameter did not correlate well with infarct volume. Of the other methods, manual tracing of the perimeter of the infarct had the lowest intraobserver and interobserver variability: coefficients of variation were 8.6% and 14.1%, respectively. For total intracranial volume, manual tracing also provided the highest reproducibility: intraobserver and interobserver coefficients of variation were 3.3% and 4.9%, respectively. CONCLUSIONS: Manual tracing of the perimeter is the most reproducible method for measuring the volumes of the infarct and the total intracranial space in multicenter trials of therapies for acute ischemic stroke.

Adult↗