Publications by authors named "Fijnvandraat Karin"

In more than half of the individuals with a clinically relevant bleeding tendency who are referred to hemostasis experts, no biological etiology can be found after extensive laboratory testing. These persons are diagnosed with an unexplained bleeding tendency or "bleeding disorder of unknown cause" (BDUC). The mucocutaneous bleeding phenotype of individuals with BDUC is generally comparable to that of individuals with inherited bleeding disorders such as von Willebrand disease or platelet function disorders.

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Article Synopsis
  • Platelet transfusions are given to preterm infants to prevent bleeding, but recent studies showed higher risks of mortality and major bleeding with transfusions at a higher platelet count threshold of 50 × 10/L compared to 25 × 10/L.
  • A prospective observational study across 64 neonatal intensive care units in 22 European countries was conducted to assess current platelet transfusion practices, which included tracking transfusion rates, indications, and patient outcomes.
  • The findings indicated that the lower transfusion threshold of 25 × 10/L is being adopted in practice, though there's considerable variation in transfusion volumes and rates, highlighting the need for further research to optimize these practices.
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The development of neutralizing antibodies (inhibitors) against coagulation factor VIII (FVIII) poses a major challenge in hemophilia A (HA) treatment. The formation of FVIII inhibitors is a CD4+ T-cell dependent mechanism which includes antigen presenting cells (APCs), B- and T-helper lymphocytes. APCs present FVIII derived peptides on major histocompatibility complex class II (MHC-II) to CD4+ Tcells.

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Background: The main complication in hemophilia A treatment is the development of inhibitory antibodies against factor (F)VIII. Immune tolerance induction, the gold standard for eradicating anti-FVIII antibodies, is efficient in only 60% to 80% of cases. This underscores the need for more efficient induction of tolerance in patients with hemophilia A with FVIII inhibitors.

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Background: Inhibitor eradication to restore factor (F)VIII efficacy is the treatment goal for persons with severe hemophilia A (HA) and inhibitors. Immune tolerance induction (ITI) is demanding and successful in about 70% of people. Until now, it has remained difficult to quantify the probability of ITI success or failure, complicating the decision to initiate or not initiate ITI.

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Background And Objectives: Routine coagulation screens at birth are still standard in some European neonatal intensive care units (NICUs), although interpretation of these results is complex in preterm infants. It is unclear to what extent local coagulation assay results agree with published reference ranges when using different analysers and reagents. We aimed to assess coagulation assay results on day 1 of life in very preterm infants admitted to the NICU.

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Background: von Willebrand disease (VWD) is the most common inherited bleeding disorder caused by quantitative or qualitative defects in von Willebrand factor (VWF). The p.M771V VWF variant leads to a severe bleeding phenotype in homozygous patients.

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  • The study investigates how patients with Von Willebrand disease (VWD) perceive the severity of their condition, highlighting a gap in understanding patient experiences alongside traditional lab measures.
  • A nationwide survey in the Netherlands included 736 VWD patients, who reported their disease severity, bleeding scores, and quality of life through a questionnaire.
  • Results show that self-reported severity aligns well with clinical classifications, and factors like type of VWD, bleeding severity, gender, treatment history, and specific lab values significantly influence patients' perception of their disease severity.
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Background: Postthrombotic syndrome (PTS) is a chronic condition following deep vein thrombosis (DVT) and is associated with pain, swelling, and restricted use of the affected limb. In pediatric age groups, its incidence and risk factors are not well-known.

Methods: This observational cohort study of all consecutive children (≤18 years) with DVT treated at the Emma Children's Hospital Amsterdam between January 2001 and January 2021 was conducted to identify incidence and risk factors for PTS in neonates aged ≤2 months and children aged >2 months.

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  • Over the years, treatment for people with hemophilia has gotten a lot better because of new scientific discoveries.
  • Despite these improvements, there are still some limits to the treatments that make us want to keep finding new options.
  • The goal is to make sure everyone with hemophilia, no matter their age or how severe it is, can get treatments that stop bleeding and let them live full lives.
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  • Type 2B Von Willebrand disease (VWD) is a bleeding disorder linked to specific genetic variations in the VWF gene, and the study aimed to explore how these genetic differences affect clinical symptoms over a 16-year period in a cohort of 64 patients.
  • The research found that 67.2% of patients experienced thrombocytopenia (low platelet counts), which was most significantly associated with the p.Arg1306Trp genetic variant, showing considerably lower platelet counts compared to another variant, p.Arg1308Cys.
  • Additionally, while some patient pregnancies led to decreased platelet counts, postpartum hemorrhages occurred despite preventative treatment, highlighting the complex relationship between genetic factors and bleeding events in affected individuals.
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Importance: Red blood cell (RBC) transfusions are frequently administered to preterm infants born before 32 weeks of gestation in the neonatal intensive care unit (NICU). Two randomized clinical trials (Effects of Transfusion Thresholds on Neurocognitive Outcomes of Extremely Low-Birth-Weight Infants [ETTNO] and Transfusion of Prematures [TOP]) found that liberal RBC transfusion thresholds are nonsuperior to restrictive thresholds, but the extent to which these results have been integrated into clinical practice since publication in 2020 is unknown.

Objective: To describe neonatal RBC transfusion practice in Europe.

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Background: To enable personalized treatment and shared decision-making in chronic care, relevant health information is collected. However, health information is often fragmented across hospital information systems, digital health apps, and questionnaire portals. This also pertains to hemophilia care, in which scattered information hampers integrated care.

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  • * The International Society on Thrombosis and Haemostasis developed a comprehensive clinical practice guideline to assist patients, caregivers, and healthcare professionals in making informed treatment decisions for congenital hemophilia A and B.
  • * A diverse panel of experts prioritized 13 key clinical questions regarding treatment strategies, utilizing the GRADE approach for systematic evidence review, and sought public feedback on their recommendations.
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  • Once-weekly efanesoctocog alfa was tested in a phase 3 study for children under 12 with severe hemophilia A, showing promising results in preventing bleeding and maintaining factor VIII activity.
  • The study enrolled 74 patients, none of whom developed factor VIII inhibitors, and most experienced non-serious adverse events during the treatment.
  • With low annualized bleeding rates and a significant percentage of patients experiencing no bleeding episodes, efanesoctocog alfa demonstrated safety and effectiveness for this age group.
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Objective: To describe the incidence of major bleeds according to different platelet counts in very preterm infants, and to explore whether this association is influenced by other risk factors for bleeding.

Design: Observational cohort study.

Setting: A Dutch tertiary care neonatal intensive care unit.

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People with nonsevere hemophilia (PWNSH) are phenotypically more diverse than those with severe hemophilia. Perceptions relating to a "nonsevere" phenotype have contributed to fewer research initiatives, fewer guidelines on optimal management, and a lack of standards for surveillance and clinical assessment for affected individuals. In many cases, episodes of abnormal bleeding could, if investigated, have led to earlier diagnosis.

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Background: Pharmacokinetic (PK)-guided dosing is used to individualize factor (F)VIII and FIX replacement therapy.

Objectives: This study investigates the reliability and feasibility of PK-guided prophylactic dosing of factor concentrates in hemophilia A and B.

Methods: In this multicenter, prospective cohort study, people of all ages with hemophilia received prophylactic treatment with factor concentrates based on individual PK parameters.

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Objectives: Anti-factor VIII (FVIII) antibodies have been reported to exhibit both neutralizing and non-neutralizing characteristics. This is the first study investigating the full spectrum of FVIII-specific antibodies, including non-neutralizing antibodies, very-low titer inhibitors, and inhibitors, in a large nationwide population of persons with hemophilia A of all severities.

Methods: All persons with hemophilia A (mild (FVIII > 5-40 IU/dL)/moderate [FVIII 1-5 IU/dL)/severe (FVIII < 1 IU/dL)] with an available plasma sample who participated in the study between 2018 and 2019 were included.

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Introduction: Non-severe haemophilia A patient can be treated with desmopressin or factor VIII (FVIII) concentrate. Combining both may reduce factor consumption, but its feasibility and safety has never been investigated.

Aim: We assessed the feasibility and safety of combination treatment in nonsevere haemophilia A patients.

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Factors influencing the activation of neutrophils in SCD and the potential neutrophil-mediated ameliorating effects of therapies in SCD.

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Article Synopsis
  • There is ongoing debate about the definition of type 1 von Willebrand disease (VWD), with previous guidelines suggesting that VWF levels <30 IU/dL indicate type 1 VWD and levels between 30 to 50 IU/dL signify low VWF.
  • A study combining data from two national cohorts found that while nearly half of type 1 VWD patients had VWF levels <30 IU/dL, a significant number showed increases to low or normal levels with age.
  • The analysis indicates that low VWF is not a separate condition but part of the evolving phenotype of age-dependent type 1 VWD, suggesting a need to reconsider current classification criteria for the disease.
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