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Featured researches published by Fop van Kooten.


The Lancet | 2012

Magnesium for aneurysmal subarachnoid haemorrhage (MASH-2): a randomised placebo-controlled trial

Sanne M. Dorhout Mees; Ale Algra; W. Peter Vandertop; Fop van Kooten; Hans A. J. M. Kuijsten; Jelis Boiten; Robert J. van Oostenbrugge; Rustam Al-Shahi Salman; Pablo M. Lavados; Gabriel J.E. Rinkel; Walter M. van den Bergh

Summary Background Magnesium sulphate is a neuroprotective agent that might improve outcome after aneurysmal subarachnoid haemorrhage by reducing the occurrence or improving the outcome of delayed cerebral ischaemia. We did a trial to test whether magnesium therapy improves outcome after aneurysmal subarachnoid haemorrhage. Methods We did this phase 3 randomised, placebo-controlled trial in eight centres in Europe and South America. We randomly assigned (with computer-generated random numbers, with permuted blocks of four, stratified by centre) patients aged 18 years or older with an aneurysmal pattern of subarachnoid haemorrhage on brain imaging who were admitted to hospital within 4 days of haemorrhage, to receive intravenous magnesium sulphate, 64 mmol/day, or placebo. We excluded patients with renal failure or bodyweight lower than 50 kg. Patients, treating physicians, and investigators assessing outcomes and analysing data were masked to the allocation. The primary outcome was poor outcome—defined as a score of 4–5 on the modified Rankin Scale—3 months after subarachnoid haemorrhage, or death. We analysed results by intention to treat. We also updated a previous meta-analysis of trials of magnesium treatment for aneurysmal subarachnoid haemorrhage. This study is registered with controlled-trials.com (ISRCTN 68742385) and the EU Clinical Trials Register (EudraCT 2006-003523-36). Findings 1204 patients were enrolled, one of whom had his treatment allocation lost. 606 patients were assigned to the magnesium group (two lost to follow-up), 597 to the placebo (one lost to follow-up). 158 patients (26·2%) had poor outcome in the magnesium group compared with 151 (25·3%) in the placebo group (risk ratio [RR] 1·03, 95% CI 0·85–1·25). Our updated meta-analysis of seven randomised trials involving 2047 patients shows that magnesium is not superior to placebo for reduction of poor outcome after aneurysmal subarachnoid haemorrhage (RR 0·96, 95% CI 0·86–1·08). Interpretation Intravenous magnesium sulphate does not improve clinical outcome after aneurysmal subarachnoid haemorrhage, therefore routine administration of magnesium cannot be recommended. Funding Netherlands Heart Foundation, UK Medical Research Council.


Stroke | 1997

Platelet Activation and Lipid Peroxidation in Patients With Acute Ischemic Stroke

Fop van Kooten; Giovanni Ciabattoni; Carlo Patrono; Diederik W.J. Dippel; Peter J. Koudstaal

BACKGROUND AND PURPOSE Both platelet activation and lipid peroxidation are potential sources of vasoactive eicosanoids that can be produced via the cyclooxygenase pathway, ie, thromboxane (TX) A2, or by free radical-catalyzed peroxidation of arachidonic acid, ie, isoprostanes. We investigated the biosynthesis of TXA2 and F2-isoprostanes, as reflected by the urinary excretion of 11-dehydro-TXB2 and 8-epi-prostaglandin (PG) F2 alpha respectively, in 62 consecutive patients (30 men, 32 women; mean age, 67 +/- 14 years) with acute ischemic stroke. METHODS At least two consecutive 6-hour urine samples were obtained during the first 72 hours after onset of symptoms. Urinary eicosanoids were measured by previously described radioimmunoassays. RESULTS Repeated periods of enhanced thromboxane biosynthesis were found in 52% of patients. Urinary 11-dehydro-TXB2 averaged 221 +/- 207 (mean +/- SD; n = 197; range, 13 to 967) pmol/mmol creatinine in 30 patients treated with cyclooxygenase inhibitors (mostly aspirin) at the time of study versus 392 +/- 392 (n = 186; range, 26 to 2533) in 32 untreated patients (P < .001). The corresponding values for 8-epi-PGF2 alpha excretion were 74 +/- 42 (range, 14 to 206) and 83 +/- 65 (range, 24 to 570) pmol/mmol creatinine (P > .05). The correlation between the two metabolites was moderate in both untreated patients (r = .41, P < .001) and patients with cyclooxygenase inhibitors (r = .31, P < .001). In a multiple regression analysis, increased thromboxane production was independently associated with severity of stroke on admission, atrial fibrillation, and treatment with cyclooxygenase-inhibiting drugs. CONCLUSIONS We conclude that during the first few days after an acute ischemic stroke (1) platelet activation occurs repeatedly in a cyclooxygenase-dependent fashion; (2) platelet activation is not associated with concurrent changes in isoprostane biosynthesis; (3) platelet activation is independently associated with stroke severity and atrial fibrillation; and (4) isoprostane biosynthesis is largely independent of platelet cyclooxygenase activity.


Journal of the American College of Cardiology | 2012

Aggressive Cardiovascular Phenotype of Aneurysms-Osteoarthritis Syndrome Caused by Pathogenic SMAD3 Variants

Denise van der Linde; Ingrid van de Laar; Aida M. Bertoli-Avella; Rogier A. Oldenburg; Jos A. Bekkers; Francesco Mattace-Raso; Anton H. van den Meiracker; Adriaan Moelker; Fop van Kooten; Ingrid M.E. Frohn-Mulder; Janneke Timmermans; Els Moltzer; Jan Maarten Cobben; Lut Van Laer; Bart Loeys; Julie De Backer; Paul Coucke; Anne De Paepe; Yvonne Hilhorst-Hofstee; Marja W. Wessels; Jolien W. Roos-Hesselink

OBJECTIVES The purpose of this study was describe the cardiovascular phenotype of the aneurysms-osteoarthritis syndrome (AOS) and to provide clinical recommendations. BACKGROUND AOS, caused by pathogenic SMAD3 variants, is a recently described autosomal dominant syndrome characterized by aneurysms and arterial tortuosity in combination with osteoarthritis. METHODS AOS patients in participating centers underwent extensive cardiovascular evaluation, including imaging, arterial stiffness measurements, and biochemical studies. RESULTS We included 44 AOS patients from 7 families with pathogenic SMAD3 variants (mean age: 42 ± 17 years). In 71%, an aortic root aneurysm was found. In 33%, aneurysms in other arteries in the thorax and abdomen were diagnosed, and in 48%, arterial tortuosity was diagnosed. In 16 patients, cerebrovascular imaging was performed, and cerebrovascular abnormalities were detected in 56% of them. Fifteen deaths occurred at a mean age of 54 ± 15 years. The main cause of death was aortic dissection (9 of 15; 60%), which occurred at mildly increased aortic diameters (range: 40 to 63 mm). Furthermore, cardiac abnormalities were diagnosed, such as congenital heart defects (6%), mitral valve abnormalities (51%), left ventricular hypertrophy (19%), and atrial fibrillation (22%). N-terminal brain natriuretic peptide (NT-proBNP) was significantly higher in AOS patients compared with matched controls (p < 0.001). Aortic pulse wave velocity was high-normal (9.2 ± 2.2 m/s), indicating increased aortic stiffness, which strongly correlated with NT-proBNP (r = 0.731, p = 0.005). CONCLUSIONS AOS predisposes patients to aggressive and widespread cardiovascular disease and is associated with high mortality. Dissections can occur at relatively mildly increased aortic diameters; therefore, early elective repair of the ascending aorta should be considered. Moreover, cerebrovascular abnormalities were encountered in most patients.


Journal of Neurology | 1997

Coagulation disorders in young adults with acute cerebral ischaemia

Alexander G. Munts; Perry J.J. van Genderen; D.W.J. Dippel; Fop van Kooten; Peter J. Koudstaal

Abstract We analysed the results of coagulation studies in an unselected series of young adults with acute cerebral ischaemia. Our aims were (a) to determine the prevalence of coagulation disorders among these patients, (b) to investigate the relation between the presence of coagulation abnormalities and large vessel disease or potential sources of cardiac embolism and (c) to evaluate the occurrence of thrombotic events in patients with or without coagulation disorders. One hundred and twenty consecutively admitted patients (53 men, 67 women, median age 38 years, range 15–45) who presented with acute cerebral infarction (n = 89) or a transient ischaemic attack (n = 31) were evaluated. Diagnostic studies consisted of electrocardiography, echocardiography, duplex scanning, and/or angiography. Coagulation studies included activity tests of protein S, protein C, antithrombin, plasminogen, measurement of immunoglobulin G (IgG) anticardiolipin antibodies (ACLA), and a dilute prothrombin assay. Initially, 30 patients had increased ACLA titres and 28 had an abnormal dilute prothrombin assay, suggesting lupus anticoagulant. Decreased protein S, protein C and antithrombin activity were detected in 20, 3 and 3 patients, respectively, excluding patients in whom the abnormalities could be explained by the use of medication, by pregnancy or puerperium. We detected a decreased activity of plasminogen in 5 patients. The disorders could be confirmed by a second assessment in only 2 patients with a protein S deficiency, in none of the patients with a protein C or antithrombin deficiency and in 1 patient with plasminogen deficiency. However, the abnormalities persisted in 19 of 21 patients with increased anticardiolipin IgG titres and in 9 of 20 patients with lupus anticoagulant. A confirmed coagulation disorder was not associated with stroke type or vascular risk factors, but it was more common among patients with large vessel disease (odds ratio: 3.8, 95% confidence interval (CI): 1.1–12.8). Sixteen patients had a recurrent thromboembolic event, but the risk of recurrence was not increased among patients with a confirmed coagulation disorder. Our results suggest that idiopathic coagulation disorders are found in about a quarter of young stroke patients. They are difficult to predict and probably interact with other risk factors.


Neurology | 2014

Cardiac dysfunction after aneurysmal subarachnoid hemorrhage: Relationship with outcome

Ivo van der Bilt; D. Hasan; Renee B.A. van den Brink; Maarten-Jan Cramer; Mathieu van der Jagt; Fop van Kooten; John H. J. M. Meertens; Maarten P. van den Berg; Rob J. M. Groen; Folkert J. ten Cate; Otto Kamp; Marco J.W. Götte; Janneke Horn; Johan Groeneveld; Peter W Vandertop; Ale Algra; Frans C. Visser; Arthur A.M. Wilde; Gabriel J.E. Rinkel

Objective: To assess whether cardiac abnormalities after aneurysmal subarachnoid hemorrhage (aSAH) are associated with delayed cerebral ischemia (DCI) and clinical outcome, independent from known clinical risk factors for these outcomes. Methods: In a prospective, multicenter cohort study, we performed echocardiography and ECG and measured biochemical markers for myocardial damage in patients with aSAH. Outcomes were DCI, death, and poor clinical outcome (death or dependency for activities of daily living) at 3 months. With multivariable Poisson regression analysis, we calculated risk ratios (RRs) with corresponding 95% confidence intervals. We used survival analysis to assess cumulative percentage of death in patients with and without echocardiographic wall motion abnormalities (WMAs). Results: We included 301 patients with a mean age of 57 years; 70% were women. A wall motion score index ≥1.2 had an adjusted RR of 1.2 (0.9–1.6) for DCI, 1.9 (1.1–3.3) for death, and 1.8 (1.1–3.0) for poor outcome. Midventricular WMAs had adjusted RRs of 1.1 (0.8–1.4) for DCI, 2.3 (1.4–3.8) for death, and 2.2 (1.4–3.5) for poor outcome. For apical WMAs, adjusted RRs were 1.3 (1.1–1.7) for DCI, 1.5 (0.8–2.7) for death, and 1.4 (0.8–2.5) for poor outcome. Elevated troponin T levels, ST-segment changes, and low voltage on the admission ECGs had a univariable association with death but were not independent predictors for outcome. Conclusion: WMAs are independent risk factors for clinical outcome after aSAH. This relation is partly explained by a higher risk of DCI. Further study should aim at treatment strategies for these aSAH-related cardiac abnormalities to improve clinical outcome.


Stroke | 2009

Withdrawal of Statins and Risk of Subarachnoid Hemorrhage

Roelof Risselada; Huub Straatman; Fop van Kooten; Diederik W.J. Dippel; Aad van der Lugt; Wiro J. Niessen; Azadeh Firouzian; Ron M. C. Herings; Miriam Sturkenboom

Background and Purpose— Vascular endothelium, which can be affected by statins, is believed to play a substantial role in subarachnoid hemorrhage (SAH). Our objective was to estimate the association between use and withdrawal of statins and the risk of SAH. Methods— We conducted a population-based case–control study within the PHARMO database. A case was defined as a person hospitalized for SAH (ICD-9-CM code 430) in the period January 1, 1998 to December 31, 2006. Ten randomly chosen controls were matched to each case on age, gender, and calendar date. Results— During the study period 1004 incident cases of SAH were identified. Current use of statins did not significantly decrease the risk of SAH (OR=0.77, 95% CI 0.55 to 1.07). The odds ratio for recent withdrawal compared to nonusers was 1.62 (95% CI 0.96 to 2.73). Compared to current use, recent withdrawal was associated with an increased risk of SAH (OR=2.34, 95% CI 1.35 to 4.05). Interaction analysis showed that the effect of statin withdrawal was highest in patients who had also recently stopped antihypertensive drugs (OR=6.77, 95% CI 2.10 to 21.8). Conclusions— Current use of statins seems to lower the risk of SAH, although the reduction was not significant in new users. Statin withdrawal increased the risk of SAH by a factor 2, even more in patients who had also recently stopped their antihypertensive treatment.


Stroke | 1996

Lipoprotein(a) in Patients With Acute Cerebral Ischemia

Fop van Kooten; Johannes van Krimpen; Diederik W.J. Dippel; Nicoline Hoogerbrugge; Peter J. Koudstaal

BACKGROUND AND PURPOSE In several cross-sectional studies, a high serum lipoprotein(a) [Lp(a)] level was found to be an independent risk factor for cerebral infarction. In a recent prospective study, however, no association was found between Lp(a) levels at baseline and future risk of stroke. Whether Lp(a) is a prognostic factor in a high-risk population of patients with acute ischemic stroke remains unclear. METHODS We assessed Lp(a) level on admission to study its relationship with cardiovascular risk profile, stroke severity, and prognosis in 151 consecutive patients with acute cerebral ischemia. The mean follow-up period was 2.5 +/- 1.2 years. Lp(a) was measured by means of a solid-phase two-site immunoradiometric assay. RESULTS Increased Lp(a) levels were found in 53 (35%) of the patients with cerebral ischemia. Median (5th and 95th percentile) values of Lp(a) were 191 (12 and 1539) mg/L and 197 (10 and 1255) mg/L for patients with transient ischemic attack and patients with ischemic stroke, respectively. No relationship was found between Lp(a) levels and stroke severity (P=.68) or the occurrence of vascular events during follow-up (P log rank=0.81). CONCLUSIONS We conclude that Lp(a) is increased in about one third of patients with acute cerebral ischemia, but it does not appear to be associated with the cardiovascular risk profile, stroke characteristics, or the prognosis of such patients.


European Journal of Radiology | 2011

Intracranial aneurysm segmentation in 3D CT angiography: Method and quantitative validation with and without prior noise filtering

Azadeh Firouzian; Rashindra Manniesing; Zwenneke H. Flach; Roelof Risselada; Fop van Kooten; Miriam Sturkenboom; Aad van der Lugt; Wiro J. Niessen

Intracranial aneurysm volume and shape are important factors for predicting rupture risk, for pre-surgical planning and for follow-up studies. To obtain these parameters, manual segmentation can be employed; however, this is a tedious procedure, which is prone to inter- and intra-observer variability. Therefore there is a need for an automated method, which is accurate, reproducible and reliable. This study aims to develop and validate an automated method for segmenting intracranial aneurysms in Computed Tomography Angiography (CTA) data. Also, it is investigated whether prior smoothing improves segmentation robustness and accuracy. The proposed segmentation method is implemented in the level set framework, more specifically Geodesic Active Surfaces, in which a surface is evolved to capture the aneurysmal wall via an energy minimization approach. The energy term is composed of three different image features, namely; intensity, gradient magnitude and intensity variance. The method requires minimal user interaction, i.e. a single seed point inside the aneurysm needs to be placed, based on which image intensity statistics of the aneurysm are derived and used in defining the energy term. The method has been evaluated on 15 aneurysms in 11 CTA data sets by comparing the results to manual segmentations performed by two expert radiologists. Evaluation measures were Similarity Index, Average Surface Distance and Volume Difference. The results show that the automated aneurysm segmentation method is reproducible, and performs in the range of inter-observer variability in terms of accuracy. Smoothing by nonlinear diffusion with appropriate parameter settings prior to segmentation, slightly improves segmentation accuracy.


Human Mutation | 2015

SMAD2 Mutations Are Associated with Arterial Aneurysms and Dissections

Dimitra Micha; Dong Chuan Guo; Yvonne Hilhorst-Hofstee; Fop van Kooten; Dian Atmaja; Eline Overwater; Ferdy K. Cayami; Ellen S. Regalado; René van Uffelen; Hanka Venselaar; Sultana Mh Faradz; Gerrit Vriend; Marjan M. Weiss; Erik A. Sistermans; Alessandra Maugeri; Dianna M. Milewicz; Gerard Pals; Fleur S. van Dijk

We report three families with arterial aneurysms and dissections in which variants predicted to be pathogenic were identified in SMAD2. Moreover, one variant occurred de novo in a proband with unaffected parents. SMAD2 is a strong candidate gene for arterial aneurysms and dissections given its role in the TGF‐β signaling pathway. Furthermore, although SMAD2 and SMAD3 probably have functionally distinct roles in cell signaling, they are structurally very similar. Our findings indicate that SMAD2 mutations are associated with arterial aneurysms and dissections and are in accordance with the observation that patients with pathogenic variants in genes encoding proteins involved in the TGF‐β signaling pathway exhibit arterial aneurysms and dissections as key features


Journal of Neurology | 1997

The Dutch Vascular Factors in Dementia Study: rationale and design

Fop van Kooten; Michiel L. Bots; Monique M.B. Breteler; Frits Haverkate; John C. van Swieten; Diederick E. Grobbee; Peter J. Koudstaal; Cornelis Kluft

Abstract Dementia is a rapidly increasing health problem in the industrialized countries. With the ageing of the population the number of demented persons increases both in relative and absolute terms. Obviously, there is a need for prevention and intervention strategies. We describe the methods and baseline findings of a large study aimed at identifying potentially modifiable vascular, thrombogenic, and metabolic determinants of dementia. The study population consists of subjects 55 years of age or older. Since the vascular wall of the cerebral vessels is different from that of the coronary or peripheral vessels, we formed three subgroups in which vascular risk factors for dementia are studied. Subjects with stroke were distinguished from subjects with coronary or peripheral artery disease, and from subjects without stroke or coronary or peripheral artery disease. To obtain a large enough number of subjects with stroke, cases and controls from a stroke registry were combined with cases and controls of a population-based study from the same region. For the diagnosis of dementia the DSM-III-R criteria were used. Extensive information on cardiovascular risk factors was collected, including indicators of atherosclerosis. Blood and urine were sampled to study platelet function and thrombogenic and metabolic factors. The study population consists of 7,466 subjects, of whom 300 were recruited from a hospital-based stroke registry. Coronary or peripheral artery disease was present in 956 subjects and stroke in 617. Dementia was present in 434 (5.8%) of all subjects. The prevalence of dementia was 3.0, 24.0, and 4.4% in subjects with a history of coronary or peripheral artery disease, a history of stroke, and subjects without a history of coronary or peripheral artery disease or stroke, respectively. The study will allow us to investigate the role of vascular factors in dementia, irrespective of its cause.

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Peter J. Koudstaal

Erasmus University Rotterdam

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Diederik W.J. Dippel

Erasmus University Rotterdam

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Gerard M. Ribbers

Erasmus University Rotterdam

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Ladbon Khajeh

Erasmus University Rotterdam

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Aad van der Lugt

Erasmus University Rotterdam

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Diederick E. Grobbee

Erasmus University Rotterdam

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Emiel Sneekes

Erasmus University Rotterdam

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Wendy Boerboom

Erasmus University Rotterdam

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