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Dive into the research topics where Karin de Boer is active.

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Featured researches published by Karin de Boer.


Circulation-cardiovascular Genetics | 2015

Clinical Presentation, Long-Term Follow-Up, and Outcomes of 1001 Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy Patients and Family Members

Judith A. Groeneweg; Aditya Bhonsale; Cynthia A. James; Anneline S.J.M. te Riele; Dennis Dooijes; Crystal Tichnell; Brittney Murray; Ans C.P. Wiesfeld; Abhishek C. Sawant; Bina Kassamali; Douwe E. Atsma; Paul G.A. Volders; Natasja M.S. de Groot; Karin de Boer; Stefan L. Zimmerman; Ihab R. Kamel; Jeroen F. van der Heijden; Stuart D. Russell; Maarten J. Cramer; Ryan J. Tedford; Pieter A. Doevendans; Toon A.B. van Veen; Harikrishna Tandri; Arthur A.M. Wilde; Daniel P. Judge; J. Peter van Tintelen; Richard N.W. Hauer; Hugh Calkins

Background—Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) is a progressive cardiomyopathy. We aimed to define long-term outcome in a transatlantic cohort of 1001 individuals. Methods and Results—Clinical and genetic characteristics and follow-up data of ARVD/C index-patients (n=439, fulfilling of 2010 criteria in all) and family members (n=562) were assessed. Mutations were identified in 276 index-patients (63%). Index-patients presented predominantly with sustained ventricular arrhythmias (268; 61%). During a median follow-up of 7 years, 301 of the 416 index-patients presenting alive (72%) experienced sustained ventricular arrhythmias. Sudden cardiac death during follow-up occurred more frequently among index-patients without an implantable cardioverter-defibrillator (10/63, 16% versus 2/335, 0.6%). Overall, cardiac mortality and the need for cardiac transplantation were low (6% and 4%, respectively). Clinical characteristics and outcomes were similar in index-patients with and without mutations, as well as in those with familial and nonfamilial ARVD/C. ARVD/C was diagnosed in 207 family members (37%). Symptoms at first evaluation correlated with disease expression. Family members with mutations were more likely to meet Task Force Criteria for ARVD/C (40% versus 18%), experience sustained ventricular arrhythmias (11% versus 1%), and die from a cardiac cause (2% versus 0%) than family members without mutations. Conclusions—Long-term outcome was favorable in diagnosed and treated ARVD/C index-patients and family members. Outcome in index-patients was modulated by implantable cardioverter-defibrillator implantation, but not by mutation status and familial background of disease. One third of family members developed ARVD/C. Outcome in family members was determined by symptoms at first evaluation and mutations.


Heart | 2012

Cardiac disease and cognitive impairment: a systematic review

Laura Eggermont; Karin de Boer; Majon Muller; A.C. Jaschke; Otto Kamp; E.J.A. Scherder

Cognitive impairment in cardiac patients may interfere with disease management. This review describes studies examining specific cognitive impairments in cardiac patients and studies that investigate the link between echocardiographic and cognitive measures. Executive function impairments were frequently reported in different patient groups. Also, lower cardiac output and worse left ventricular diastolic function are linked to executive function deficits. In cardiac patients, special attention should be paid to these executive function impairments in view of their role in disease management and independent living. Interventions that stimulate executive function should be encouraged and integrated in cardiac treatment protocols.


European Heart Journal | 2011

Manifest disease, risk factors for sudden cardiac death, and cardiac events in a large nationwide cohort of predictively tested hypertrophic cardiomyopathy mutation carriers: determining the best cardiological screening strategy

Imke Christiaans; Erwin Birnie; Gouke J. Bonsel; Marcel Mannens; Michelle Michels; Danielle Majoor-Krakauer; Dennis Dooijes; J. Peter van Tintelen; Maarten P. van den Berg; Paul G.A. Volders; Yvonne Arens; Arthur van den Wijngaard; Douwe E. Atsma; Apollonia T.J.M. Helderman-van den Enden; Arjan C. Houweling; Karin de Boer; Jasper J. van der Smagt; Richard N.W. Hauer; Carlo Marcelis; Janneke Timmermans; Irene M. van Langen; Arthur A.M. Wilde

AIMS We investigated the presence of a clinical diagnosis of hypertrophic cardiomyopathy (HCM), risk factors for sudden cardiac death (SCD), and cardiac events during follow-up in predictively tested-not known to have a clinical diagnosis of HCM before the DNA test-carriers of a sarcomeric gene mutation and associations with age and gender to determine the best cardiological screening strategy. METHODS AND RESULTS One hundred and thirty-six (30%) of 446 mutation carriers were diagnosed with HCM at one or more cardiological evaluation(s). Male gender and higher age were associated with manifest disease. Incidence of newly diagnosed manifest HCM was <10% per person-year under the age of 40 years and >10% in older carriers, although numbers were small in carriers <15 years. Twenty-three percent of carriers, with and without manifest disease, had established risk factor(s) for SCD (no significant difference). During an average follow-up of 3.5 ± 1.7 years two carriers, both with manifest disease, died suddenly (0.13% per person-year). A high-risk status for SCD (≥2 risk factors and manifest HCM) was present in 17 carriers during follow-up (2.4% per person-year). Age but not gender was associated with a high-risk status for SCD. CONCLUSION Thirty percent of carriers had or developed manifest HCM after predictive DNA testing and risk factors for SCD were frequently present. Our data suggest that the SCD risk is low and risk stratification for SCD can be omitted in carriers without manifest disease and that frequency of cardiological evaluations can possibly be decreased in carriers between 15 and 40 years as long as hypertrophy is absent.


Sexually Transmitted Diseases | 1997

Clearance of Cervical Human Papillomavirus Infection by Treatment for Cervical Dysplasia

Liesbeth J.M. Bollen; Steven P. Tjong-A-Hung; J. Van Der Velden; Ben Willem J. Mol; Karin de Boer; F. J. W. Ten Kate; Otto P. Bleker; J. Ter Schegget

Objectives: The aim of this study was to investigate the prevalence of human papillomavirus (HPV) after treatment for cervical dysplasia. Study Design: The presence of HPV was investigated in cervical scrapes of 91 patients, before and after treatment, using consensus primers in the polymerase chain reaction. Results: Before treatment for cervical dysplasia, 89 of 91 patients (98%) were HPV‐positive compared with 28 of 91 patients (31%) after treatment. The HPV type present before treatment was found in the scrapes of only 9 of 89 patients (10%). Detection of HPV after treatment was associated with human immunodeficiency virus infection and incomplete conization. Conclusion: The HPV type present before treatment was frequently cleared by treatment for cervical dysplasia.


Journal of Cardiovascular Magnetic Resonance | 2014

In-vivo T1 cardiovascular magnetic resonance study of diffuse myocardial fibrosis in hypertrophic cardiomyopathy

Wessel P. Brouwer; Emma N. Baars; Tjeerd Germans; Karin de Boer; Aernout M. Beek; Jolanda van der Velden; Albert C. van Rossum; Mark B.M. Hofman

BackgroundIn hypertrophic cardiomyopathy (HCM), autopsy studies revealed both increased focal and diffuse deposition of collagen fibers. Late gadolinium enhancement imaging (LGE) detects focal fibrosis, but is unable to depict interstitial fibrosis. We hypothesized that with T1 mapping, which is employed to determine the myocardial extracellular volume fraction (ECV), can detect diffuse interstitial fibrosis in HCM patients.MethodsT1 mapping with a modified Look-Locker Inversion Recovery (MOLLI) pulse sequence was used to calculate ECV in manifest HCM (n = 16) patients and in healthy controls (n = 14). ECV was determined in areas where focal fibrosis was excluded with LGE.ResultsThe total group of HCM patients showed no significant changes in mean ECV values with respect to controls (0.26 ± 0.03 vs 0.26 ± 0.02, p = 0.83). Besides, ECV in LGE positive HCM patients was comparable with LGE negative HCM patients (0.27 ± 0.03 vs 0.25 ± 0.03, p = 0.12).ConclusionsThis study showed that HCM patients have a similar ECV (e.g. interstitial fibrosis) in myocardium without LGE as healthy controls. Therefore, the additional clinical value of T1 mapping in HCM seems limited, but future larger studies are needed to establish the clinical and prognostic potential of this new technique within HCM.


BMC Pregnancy and Childbirth | 2007

Disproportionate Intrauterine Growth Intervention Trial At Term: DIGITAT

Kim Boers; Denise Bijlenga; Ben Willem J. Mol; Saskia LeCessie; Erwin Birnie; Marielle van Pampus; Rob H. Stigter; Kitty W. M. Bloemenkamp; Claudia A. van Meir; Joris A. M. van der Post; Dick J. Bekedam; Lucy S. M. Ribbert; Addie P. Drogtrop; Paulien van der Salm; Anjoke J. M. Huisjes; Christine Willekes; Frans J.M.E. Roumen; Hubertina C. J. Scheepers; Karin de Boer; Johannes J. Duvekot; Jim Thornton; Sicco Scherjon

BackgroundAround 80% of intrauterine growth restricted (IUGR) infants are born at term. They have an increase in perinatal mortality and morbidity including behavioral problems, minor developmental delay and spastic cerebral palsy. Management is controversial, in particular the decision whether to induce labour or await spontaneous delivery with strict fetal and maternal surveillance. We propose a randomised trial to compare effectiveness, costs and maternal quality of life for induction of labour versus expectant management in women with a suspected IUGR fetus at term.Methods/designThe proposed trial is a multi-centre randomised study in pregnant women who are suspected on clinical grounds of having an IUGR child at a gestational age between 36+0 and 41+0 weeks. After informed consent women will be randomly allocated to either induction of labour or expectant management with maternal and fetal monitoring. Randomisation will be web-based. The primary outcome measure will be a composite neonatal morbidity and mortality. Secondary outcomes will be severe maternal morbidity, maternal quality of life and costs. Moreover, we aim to assess neurodevelopmental and neurobehavioral outcome at two years as assessed by a postal enquiry (Child Behavioral Check List-CBCL and Ages and Stages Questionnaire-ASQ). Analysis will be by intention to treat. Quality of life analysis and a preference study will also be performed in the same study population. Health technology assessment with an economic analysis is part of this so called Digitat trial (Disproportionate Intrauterine Growth Intervention Trial At Term). The study aims to include 325 patients per arm.DiscussionThis trial will provide evidence for which strategy is superior in terms of neonatal and maternal morbidity and mortality, costs and maternal quality of life aspects. This will be the first randomised trial for IUGR at term.Trial registrationDutch Trial Register and ISRCTN-Register: ISRCTN10363217.


Journal of Cardiac Failure | 2009

The Potential Role of Erythropoietin in Chronic Heart Failure: From the Correction of Anemia to Improved Perfusion and Reduced Apoptosis?

Stefan Timmer; Karin de Boer; Paul Knaapen; Marco J.W. Götte; A.C. Van Rossum

Besides stimulating erythropoiesis, erythropoietin (EPO) exerts powerful proangiogenic and antiapoptotic effects. These erythropoiesis-independent effects are potentially useful as a supplement for the treatment of chronic heart failure (CHF). EPO may improve microvascular capacity of ischemic myocardial tissue and could thereby (partially) restore myocardial function. In addition, EPO could protect cardiomyocytes from hypoxic damage and prevent them from apoptosis. However, the clinical value of these erythropoiesis-independent effects for the treatment of CHF remains to be elucidated. Small-sized trials evaluating the effects of EPO treatment on surrogate endpoints in patients with CHF showed positive effects in general; however, their mutual results are not always unambiguous. Moreover, increasing hematocrit levels with EPO has been associated with increased blood viscosity and an inherent risk of thromboembolic events. A currently running multicenter phase III trial is designed to provide clarity concerning the effects of EPO on outcome and safety in patients with CHF. Focusing primarily on outcome, however, does not provide insight into the mode of action and isolated benefits of the erythropoiesis-independent effects of EPO. Further exploration of these effects is a key issue to gain knowledge of the full potential of EPO for the treatment of CHF.


British Journal of Obstetrics and Gynaecology | 1995

Circadian variation of urinary albumin excretion in pregnancy

C. E. Douma; J.A. van der Post; B. A. C. van Acker; Karin de Boer; Marion G. Koopman

Objective The hypothesis was tested that circadian variations in urinary albumin excretion of pregnant women in the third trimester of normal pregnancy are different from nonpregnant individuals.


European Journal of Echocardiography | 2013

Comparison of three-dimensional echocardiographic software packages for assessment of left ventricular mechanical dyssynchrony and prediction of response to cardiac resynchronization therapy

Mohamed F.A. Aly; Sebastiaan A. Kleijn; Karin de Boer; Yasser A. Abd El-Hady; Khalid A. Sorour; Hossam I. Kandil; Albert C. van Rossum; Otto Kamp

AIMS We directly compared TomTec and QLAB software packages for the three-dimensional echocardiographic (3DE) assessment of left ventricular (LV) dyssynchrony including their ability to predict response to cardiac resynchronization therapy (CRT) in patients with ischaemic and non-ischaemic cardiomyopathy. METHODS AND RESULTS A total of 140 heart failure patients with the LVEF ≤35% and 60 healthy volunteers underwent 3DE. A subgroup of 60 patients underwent CRT and were evaluated before and 6-12 months after implantation. The systolic dyssynchrony index (SDI) was derived from the dispersion of time to minimum regional volume for all 16 LV segments and measured with both software packages and compared using Pearsons correlation and Bland-Altman analysis. Measurements of SDI were significantly higher using TomTec compared with QLAB in both patients (10.9 ± 3.8 vs. 9.7 ± 3.9, P < 0.001) and healthy volunteers (4.1 ± 0.8 vs. 2.4 ± 1, P < 0.001), with large biases and wide limits of agreement. A moderate correlation (r = 0.65, P < 0.001) was observed between both software packages in patients while their inter-observer and intra-observer reliability were good. Of the 60 patients undergoing CRT, reverse remodelling as a measure of response was observed in 41 patients (68%). The optimal SDI cut-off value to predict response to CRT was higher for TomTec than for QLAB (8.8 vs.7.3%, P < 0.001) and demonstrated better sensitivity and specificity (93 and 61%, respectively) compared with QLAB (88 and 33%, respectively). Response prediction in patients with non-ischaemic cardiomyopathy was excellent with a sensitivity and specificity of 95 and 100% for TomTec and 70 and 83% for QLAB using similar cut-off values of 9.1 and 9.2%, respectively. CONCLUSION Different 3DE software packages for the assessment of mechanical dyssynchrony should not be used interchangeably until better software standardization is achieved. Dyssynchrony assessment with 3DE for the prediction of response to CRT seems particularly useful in patients with non-ischaemic cardiomyopathy.


European Journal of Obstetrics & Gynecology and Reproductive Biology | 2013

Economic analysis comparing induction of labour and expectant management for intrauterine growth restriction at term (DIGITAT trial)

Sylvia M. C. Vijgen; Kim Boers; Brent C. Opmeer; Denise Bijlenga; Dick J. Bekedam; Kitty W. M. Bloemenkamp; Karin de Boer; Henk A. Bremer; Saskia le Cessie; Friso M.C. Delemarre; Johannes J. Duvekot; Tom H.M. Hasaart; Anneke Kwee; Jan M. M. van Lith; Claudia A. van Meir; Maria G. van Pampus; Joris A. M. van der Post; Monique Rijken; Frans J.M.E. Roumen; Paulien van der Salm; Marc Spaanderman; Christine Willekes; Ella Wijnen; Ben Willem J. Mol; Sicco Scherjon

OBJECTIVE Pregnancies complicated by intrauterine growth restriction (IUGR) are at increased risk for neonatal morbidity and mortality. The Dutch nationwide disproportionate intrauterine growth intervention trial at term (DIGITAT trial) showed that induction of labour and expectant monitoring were comparable with respect to composite adverse neonatal outcome and operative delivery. In this study we compare the costs of both strategies. STUDY DESIGN A cost analysis was performed alongside the DIGITAT trial, which was a randomized controlled trial in which 650 women with a singleton pregnancy with suspected IUGR beyond 36 weeks of pregnancy were allocated to induction or expectant management. Resource utilization was documented by specific items in the case report forms. Unit costs for clinical resources were calculated from the financial reports of participating hospitals. For primary care costs Dutch standardized prices were used. All costs are presented in Euros converted to the year 2009. RESULTS Antepartum expectant monitoring generated more costs, mainly due to longer antepartum maternal stays in hospital. During delivery and the postpartum stage, induction generated more direct medical costs, due to longer stay in the labour room and longer duration of neonatal high care/medium care admissions. From a health care perspective, both strategies generated comparable costs: on average €7106 per patient for the induction group (N=321) and €6995 for the expectant management group (N=329) with a cost difference of €111 (95%CI: €-1296 to 1641). CONCLUSION Induction of labour and expectant monitoring in IUGR at term have comparable outcomes immediately after birth in terms of obstetrical outcomes, maternal quality of life and costs. Costs are lower, however, in the expectant monitoring group before 38 weeks of gestation and costs are lower in the induction of labour group after 38 weeks of gestation. So if induction of labour is considered to pre-empt possible stillbirth in suspected IUGR, it is reasonable to delay until 38 weeks, with watchful monitoring.

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