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    <title>Nederkoorn, P.J.</title>
    <link>http://repub.eur.nl/res/aut/15874/</link>
    <description>List of Publications</description>
    <language>en</language>
    <image>
      <url>http://repub.eur.nl/static-eur/img/logo.png</url>
      <title>RePub, Erasmus University Rotterdam</title>
      <link>http://repub.eur.nl</link>
    </image>
    <item>
      <title>New ischaemic brain lesions on MRI after stenting or endarterectomy for symptomatic carotid stenosis: a substudy of the International Carotid Stenting Study (ICSS) (Article)</title>
      <link>http://repub.eur.nl/res/pub/18612/</link>
      <pubDate>2010-04-01T00:00:00Z</pubDate>
      <description>Background: The International Carotid Stenting Study (ICSS) of stenting and endarterectomy for symptomatic carotid stenosis found a higher incidence of stroke within 30 days of stenting compared with endarterectomy. We aimed to compare the rate of ischaemic brain injury detectable on MRI between the two groups. Methods: Patients with recently symptomatic carotid artery stenosis enrolled in ICSS were randomly assigned in a 1:1 ratio to receive carotid artery stenting or endarterectomy. Of 50 centres in ICSS, seven took part in the MRI substudy. The protocol specified that MRI was done 1-7 days before treatment, 1-3 days after treatment (post-treatment scan), and 27-33 days after treatment. Scans were analysed by two or three investigators who were masked to treatment. The primary endpoint was the presence of at least one new ischaemic brain lesion on diffusion-weighted imaging (DWI) on the post-treatment scan. Analysis was per protocol. This is a substudy of a registered trial, ISRCTN 25337470. Findings: 231 patients (124 in the stenting group and 107 in the endarterectomy group) had MRI before and after treatment. 62 (50%) of 124 patients in the stenting group and 18 (17%) of 107 patients in the endarterectomy group had at least one new DWI lesion detected on post-treatment scans done a median of 1 day after treatment (adjusted odds ratio [OR] 5·21, 95% CI 2·78-9·79; p&lt;0·0001). At 1 month, there were changes on fluid-attenuated inversion recovery sequences in 28 (33%) of 86 patients in the stenting group and six (8%) of 75 in the endarterectomy group (adjusted OR 5·93, 95% CI 2·25-15·62; p=0·0003). In patients treated at a centre with a policy of using cerebral protection devices, 37 (73%) of 51 in the stenting group and eight (17%) of 46 in the endarterectomy group had at least one new DWI lesion on post-treatment scans (adjusted OR 12·20, 95% CI 4·53-32·84), whereas in those treated at a centre with a policy of unprotected stenting, 25 (34%) of 73 patients in the stenting group and ten (16%) of 61 in the endarterectomy group had new lesions on DWI (adjusted OR 2·70, 1·16-6·24; interaction p=0·019). Interpretation: About three times more patients in the stenting group than in the endarterectomy group had new ischaemic lesions on DWI on post-treatment scans. The difference in clinical stroke risk in ICSS is therefore unlikely to have been caused by ascertainment bias. Protection devices did not seem to be effective in preventing cerebral ischaemia during stenting. DWI might serve as a surrogate outcome measure in future trials of carotid interventions. Funding: UK Medical Research Council, the Stroke Association, Sanofi-Synthélabo, European Union, Netherlands Heart Foundation, and Mach-Gaensslen Foundation.</description>
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      <title>Minor head injury: CT-based strategies for management--a cost-effectiveness analysis (Article)</title>
      <link>http://repub.eur.nl/res/pub/21238/</link>
      <pubDate>2010-02-01T00:00:00Z</pubDate>
      <description>Purpose: To compare the cost-effectiveness of using selective computed tomographic (CT) strategies with that of performing CT in all patients with minor head injury (MHI).
Materials and methods: The internal review board approved the study; written informed consent was obtained from all interviewed patients. Five strategies were evaluated, with CT performed in all patients with MHI; selectively according to the New Orleans criteria (NOC), Canadian CT head rule (CCHR), or CT in head injury patients (CHIP) rule; or in no patients. A decision tree was used to analyze short-term costs and effectiveness, and a Markov model was used to analyze long-term costs and effectiveness. n-Way and probabilistic sensitivity analyses and value-of-information (VOI) analysis were performed. Data from the multicenter CHIP Study involving 3181 patients with MHI were used. Outcome measures were first-year and lifetime costs, quality-adjusted life-years, and incremental cost-effectiveness ratios.
Results: Study results showed that performing CT selectively according to the CCHR or the CHIP rule could lead to substantial U.S. cost savings ($120 million and $71 million, respectively), and the CCHR was the most cost-effective at reference-case analysis. When the prediction rule had lower than 97% sensitivity for the identification of patients who required neurosurgery, performing CT in all patients was cost-effective. The CHIP rule was most likely
to be cost-effective. At VOI analysis, the expected value of perfect information was $7 billion, mainly because of uncertainty about long-term functional outcomes.
Conclusion: Selecting patients with MHI for CT renders cost savings and may be cost-effective, provided the sensitivity for the identification of patients who require neurosurgery is extremely high. Uncertainty regarding long-term functional outcomes after MHI justifies the routine use of CT in all patients with these injuries.</description>
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      <title>Preventive antibiotics for infections in acute stroke: A systematic review and meta-analysis (Article)</title>
      <link>http://repub.eur.nl/res/pub/17572/</link>
      <pubDate>2009-09-01T00:00:00Z</pubDate>
      <description>Objective: To provide a systematic overview and meta-analysis of randomized clinical trials evaluating preventive antibiotics in patients with acute stroke. Data Sources: The MEDLINE (1966-February 2009) and Cochrane databases and reference lists of retrieved articles. Study Selection: Randomized controlled trials on preventive antibiotic treatment in stroke. For inclusion, at least case fatality or infection rate had to be recorded. Data Extraction: Each study was scored for methodological key issues and appraised by the Jadad scale. We extracted the data using a predetermined protocol and included all patients who were randomized or who started therapy in an intent-to-treat analysis. Data Synthesis: We identified 4 randomized clinical trials including 426 patients; 94% had ischemic stroke. Study interventions were fluoroquinolones in 2 and tetracycline or a combination of β-lactam antibiotic with β-lactamase inhibitor in 1. Therapy was started within 24 hours of stroke onset. Duration of therapy varied between 3 and 5 days. The methodological quality ranged from 2 to 5 on the Jadad scale, and studies were subject to potential bias. The proportion of patients with infection was significantly smaller in the antibiotic group than in the placebo/control group (32 of 136 [23.5%] vs 53 of 139 [38.1%] patients). The pooled odds ratio for infection was 0.44 (95% confidence interval, 0.23-0.86). Ten of 210 patients (4.8%) in the antibiotic group died, compared with 13 of 216 (6.0%) in the placebo/control group. The pooled odds ratio for mortality was 0.63 (95% confidence interval, 0.22-1.78). No major harm or toxicity was reported. Conclusions: In adults with acute stroke, preventive antibiotics reduced the risk of infection, but did not reduce mortality. The observed effect warrants evaluation of preventive antibiotics in large stroke trials.</description>
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      <title>Outcome after Complicated Minor Head Injury (Article)</title>
      <link>http://repub.eur.nl/res/pub/20891/</link>
      <pubDate>2008-03-01T00:00:00Z</pubDate>
      <description>BACKGROUND AND PURPOSE: Functional outcome in patients with minor head injury with neurocranial traumatic findings on CT is largely unknown. We hypothesized that certain CT findings may be predictive of poor functional outcome. Materials and METHODS: All patients from the CT in Head Injury Patients (CHIP) study with neurocranial traumatic CT findings were included. The CHIP study is a prospective, multicenter study of consecutive patients, &gt; or =16 years of age, presenting within 24 hours of blunt head injury, with a Glasgow Coma Scale (GCS) score of 13-14 or a GCS score of 15 and a risk factor. Primary outcome was functional outcome according to the Glasgow Outcome Scale (GOS). Other outcome measures were the modified Rankin Scale (mRS), the Barthel Index (BI), and number and severity of postconcussive symptoms. The association between CT findings and outcome was assessed by using univariable and multivariable regression analysis. RESULTS: GOS was assessed in 237/312 patients (76%) at an average of 15 months after injury. There was full recovery in 150 patients (63%), moderate disability in 70 (30%), severe disability in 7 (3.0%), and death in 10 (4.2%). Outcome according to the mRS and BI was also favorable in most patients, but 82% of patients had postconcussive symptoms. Evidence of parenchymal damage was the only independent predictor of poor functional outcome (odds ratio = 1.89, P = .022). CONCLUSION: Patients with neurocranial complications after minor head injury generally make a good functional recovery, but postconcussive symptoms may persist. Evidence of parenchymal damage on CT was predictive of poor functional outcome.</description>
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      <title>Minor head injury: Guidelines for the Use of CT - A Multicenter Validation Study (Article)</title>
      <link>http://repub.eur.nl/res/pub/21490/</link>
      <pubDate>2007-12-01T00:00:00Z</pubDate>
      <description>Abstract

PURPOSE: To prospectively and externally validate published national and international guidelines for the indications of computed tomography (CT) in patients with a minor head injury.

MATERIALS AND METHODS: The study protocol was institutional review board approved. All patients implicitly consented to use of their deidentified data for research purposes. Between February 2002 and August 2004, data were collected in consecutive adult patients with blunt minor head injury (Glasgow Coma Scale score of 13-14 or 15) and a risk factor for neurocranial traumatic complications at presentation at four Dutch university hospitals. Primary outcome was any neurocranial traumatic CT finding. Secondary outcomes were clinically relevant traumatic CT findings and neurosurgical intervention. Sensitivity and specificity of each guideline for all outcomes and the number of patients needed to scan to detect one outcome (ie, the number of patients needed to undergo CT to find one patient with a neurocranial traumatic CT finding, a clinically relevant traumatic CT finding, or a CT finding that required neurosurgical intervention) were estimated.

RESULTS: Data were available for 3181 patients. Only the European Federation of Neurological Societies guidelines reached a sensitivity of 100% for all outcomes. Specificity was 0.0%-0.5%. The Dutch guidelines had the lowest sensitivity (76.5%) for neurosurgical interventions. The best specificities for traumatic CT findings and neurosurgical interventions were reached with the criteria proposed by the United Kingdom National Institute for Clinical Excellence (NICE) (46.1% and 43.6%, respectively), albeit at relatively low sensitivities (82.1% and 94.1%, respectively). The number of patients needed to scan ranged from six to 13 for traumatic CT findings and from 79 to 193 for neurosurgical interventions.

CONCLUSION: All validated guidelines demonstrated a trade-off between sensitivity and specificity. The lowest number of patients needed to scan for either of the outcomes was reached with the NICE criteria. Supplemental material: radiology.rsnajnls.org/cgi/content/full/2452061509/DC1</description>
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      <title>A history of loss of consciousness or post-traumatic amnesia in minor head injury: "conditio sine qua non" or one of the risk factors? (Article)</title>
      <link>http://repub.eur.nl/res/pub/20885/</link>
      <pubDate>2007-04-01T00:00:00Z</pubDate>
      <description>OBJECTIVE: A history of loss of consciousness (LOC) or post-traumatic amnesia (PTA) is commonly considered a prerequisite for minor head injury (MHI), although neurocranial complications also occur when LOC/PTA are absent, particularly in the presence of other risk factors. The purpose of this study was to evaluate whether known risk factors for complications after MHI in the absence of LOC/PTA have the same predictive value as when LOC/PTA are present. METHODS: A prospective multicentre study was performed in four university hospitals between February 2002 and August 2004 of consecutive blunt head injury patients (&gt; or = 16 years) presenting with a normal level of consciousness and a risk factor. Outcome measures were any neurocranial traumatic CT finding and neurosurgical intervention. Common odds ratios (OR) were estimated for each of the risk factors and tested for homogeneity. RESULTS: 2462 patients were included: 1708 with and 754 without LOC/PTA. Neurocranial traumatic findings on CT were present in 7.5% and were more common when LOC/PTA was present (8.7%). Neurosurgical intervention was required in 0.4%, irrespective of the presence of LOC/PTA. ORs were comparable across the two subgroups (p&gt;0.05), except for clinical evidence of a skull fracture, with high ORs both when LOC/PTA was present (OR = 37, 95% CI 17 to 80) or absent (OR = 6.9, 95% CI 1.8 to 27). LOC and PTA had significant ORs of 1.9 (95% CI 1.0 to 2.7) and 1.7 (95% CI 1.3 to 2.3), respectively. CONCLUSION: Known risk factors have comparable ORs in MHI patients with or without LOC or PTA. MHI patients without LOC or PTA need to be explicitly considered in clinical guidelines.</description>
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      <title>Predicting Intracranial Traumatic Findings on Computed Tomography in Patients with Minor Head Injury: The CHIP Prediction Rule (Article)</title>
      <link>http://repub.eur.nl/res/pub/20889/</link>
      <pubDate>2007-03-01T00:00:00Z</pubDate>
      <description>Abstract

BACKGROUND: Prediction rules for patients with minor head injury suggest that the use of computed tomography (CT) may be limited to certain patients at risk for intracranial complications. These rules apply only to patients with a history of loss of consciousness, which is frequently absent.

OBJECTIVE: To develop a prediction rule for the use of CT in patients with minor head injury, regardless of the presence or absence of a history of loss of consciousness.

DESIGN: Prospective, observational study.

SETTING: 4 university hospitals in the Netherlands that participated in the CT in Head Injury Patients (CHIP) study.

PATIENTS: Consecutive adult patients with minor head injury (&gt; or =16 years of age) with a Glasgow Coma Scale (GCS) score of 13 to 14 or with a GCS score of 15 and at least 1 risk factor.

MEASUREMENTS: Outcomes were any intracranial traumatic CT finding and neurosurgical intervention. The authors performed logistic regression analysis by using variables from existing prediction rules and guidelines, with internal validation by using bootstrapping.

RESULTS: 3181 patients were included (February 2002 to August 2004): 243 (7.6%) had intracranial traumatic CT findings and 17 (0.5%) underwent neurosurgical intervention. A detailed prediction rule was developed from which a simple rule was derived. Sensitivity of both rules was 100% for neurosurgical interventions, with an associated specificity of 23% to 30%. For intracranial traumatic CT findings, sensitivity and specificity were 94% to 96% and 25% to 32%, respectively. Potential CT reduction by implementing the prediction rule was 23% to 30%. Internal validation showed slight optimism for the model's performance.

LIMITATION: External validation of the prediction model will be required.

CONCLUSION: The authors propose the highly sensitive CHIP prediction rule for the selective use of CT in patients with minor head injury with or without loss of consciousness.</description>
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      <title>Diagnostic performance of duplex ultrasound in patients suspected of carotid artery disease: the ipsilateral versus contralateral artery. (Article)</title>
      <link>http://repub.eur.nl/res/pub/13913/</link>
      <pubDate>2005-10-01T00:00:00Z</pubDate>
      <description>BACKGROUND AND PURPOSE: To evaluate duplex ultrasonographic thresholds for the determination of 70% to 99% stenosis of the ipsilateral and contralateral internal carotid artery in patients with symptoms of amaurosis fugax, transient ischemic attack (TIA), or minor stroke based on 2 criteria: maximizing accuracy and optimizing cost-effectiveness and to compare these with current recommendations. METHODS: From January 1997 to January 2000, a prospective multicenter study was conducted including 350 consecutive patients with symptoms of amaurosis fugax, TIA, or minor stroke who underwent bilateral duplex ultrasonography and digital subtraction angiography. A linear regression analysis was performed to estimate the degree of angiographic stenosis as a function of the peak systolic velocity (PSV). PSV thresholds were calculated for the ipsilateral and contralateral carotid arteries based on maximizing accuracy and optimizing cost-effectiveness. RESULTS: The PSV measurements significantly overestimated the angiographic stenosis in the contralateral artery (9.5%; 95% CI, 6.3% to 12.7%) compared with the ipsilateral carotid artery. The recommended PSV threshold for the diagnosis of 70% to 99% stenosis is 230 cm/s. Maximizing accuracy, the optimal PSV threshold for the ipsilateral artery was 280 cm/s, and for the contralateral artery, 370 cm/s for diagnosing a 70% to 99% stenosis. Optimizing cost-effectiveness, the optimal PSV threshold was 220 cm/s for ipsilateral and 290 cm/s for contralateral carotid arteries. CONCLUSIONS: PSV measurements overestimate the degree of angiographic stenosis in the contralateral carotid artery in patients with symptoms of amaurosis fugax, TIA, or minor stroke. Separate PSV thresholds should be used for the ipsilateral and contralateral carotid artery. PSV thresholds that optimize cost-effectiveness differ from the recommended thresholds and from thresholds that maximize accuracy.</description>
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      <title>External validation of the Canadian CT Head Rule and the New Orleans Criteria for CT scanning in patients with minor head injury. (Article)</title>
      <link>http://repub.eur.nl/res/pub/13926/</link>
      <pubDate>2005-09-28T00:00:00Z</pubDate>
      <description>CONTEXT: Two decision rules for indications of computed tomography (CT) in patients with minor head injury, the Canadian CT Head Rule (CCHR) and the New Orleans Criteria (NOC), suggest that CT scanning may be restricted to patients with certain risk factors, which would lead to important reductions in the use of CT scans. OBJECTIVE: To validate and compare these 2 published decision rules in Dutch patients with head injuries. DESIGN, SETTING, AND PATIENTS: A prospective multicenter study conducted between February 11, 2002, and August 31, 2004, in 4 university hospitals in the Netherlands of 3181 consecutive adult patients with minor head injury who presented with a Glasgow Coma Scale (GCS) score of 13 to 14 or with a GCS score of 15 and at least 1 risk factor. MAIN OUTCOME MEASURES: Primary outcome was any neurocranial traumatic finding on CT scan. Secondary outcomes were neurosurgical intervention and clinically important CT findings. Sensitivity and specificity were estimated for each outcome for the CCHR and the NOC, using both rules as originally derived and also as adapted to apply to an expanded patient population. RESULTS: Of 3181 patients with a GCS score of 13 to 15, neurosurgical intervention was performed in 17 patients (0.5%); neurocranial traumatic CT findings were present in 312 patients (9.8%). Sensitivity for neurosurgical intervention was 100% for both the CCHR and the NOC. The NOC had a higher sensitivity for neurocranial traumatic findings and for clinically important findings (97.7%-99.4%) than did the CCHR (83.4%-87.2%). Specificities were very low for the NOC (3.0%-5.6%) and higher for the CCHR (37.2%-39.7%). The estimated potential reduction in CT scans for patients with minor head injury would be 3.0% for the adapted NOC and 37.3% for the adapted CCHR. CONCLUSIONS: For patients with minor head injury and a GCS score of 13 to 15, the CCHR has a lower sensitivity than the NOC for neurocranial traumatic or clinically important CT findings, but would identify all cases requiring neurosurgical intervention, and has greater potential for reducing the use of CT scans.</description>
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