The Incidence and Characteristics of Venous Thromboembolisms in Paediatric-Onset Inflammatory Bowel Disease: A Prospective International Cohort Study Based on the PIBD-SETQuality Safety Registry.

BACKGROUND AND AIMS: Guidelines regarding thromboprophylaxis for venous thromboembolisms [VTEs] in children with inflammatory bowel disease [IBD] are based on limited paediatric evidence. We aimed to prospectively assess the incidence of VTEs in paediatric-onset IBD [PIBD], characterize PIBD patients with a VTE and identify potential IBD-related risk factors. METHODS: From October 2016 to September 2020, paediatric gastroenterologists prospectively replied to the international Safety Registry, monthly indicating whether they had observed a VTE case in a patient <19 years with IBD. IBD details [type, Paris classification, clinical and biochemical disease activity, treatment] and VTE details [type, location, treatment, outcome] were collected. To estimate VTE incidence, participants annually reported the number of PIBD patients, data source and catchment area of their centre. A systematic literature review and meta-analysis was performed to calculate the VTE incidence in the general paediatric population. RESULTS: Participation of 129 PIBD centres resulted in coverage of 24 802 PIBD patients. Twenty cases of VTE were identified [30% Crohn's disease]. The incidence of VTEs was 3.72 (95% confidence interval [CI] 2.27-5.74) per 10 000 person-years, 14-fold higher than in the general paediatric population (0.27 [95% CI 0.18-0.38], p < 0.001). Cerebral sinus venous thrombosis was most frequently reported [50%]. All but one patient had active IBD, 45% were using steroids and 45% were hospitalized. No patient received thromboprophylaxis, whereas according to current PIBD guidelines, this was recommended in 4/20 patients. CONCLUSION: There is an increased risk of VTEs in the PIBD population compared to the general paediatric population. Awareness of VTE occurrence and prevention should be extended to all PIBD patients with active disease, especially those hospitalized.

Results of a multinational survey of diagnostic and management practices of thromboembolic pulmonary embolism in children.

INTRODUCTION: The incidence of thromboembolic (TE)-pediatric pulmonary embolism (PPE) is increasing. We sought to evaluate current practice patterns and gaps in the management of TE-PPE. MATERIALS AND METHODS: After Institutional Review Board approval, SurveyMonkey® questions were sent to members of the Pediatric/Neonatal Thrombosis and Hemostasis Subcommittee, of the International Society on Thrombosis and Haemostasis and the Hemostasis and Thrombosis Research Society. RESULTS: Of 442 members of the two groups, 134 (30%) responded, and 125 (28%) complete responses were analyzed. Eighty percent practiced at a pediatric facility, 88% at academic centers, and 59% in the USA. Computed tomography pulmonary angiography (CTPA) was the preferred diagnostic modality (89%). D-dimer testing was variably used; 22% used clinical diagnostic prediction models and 8% had specific clinical care pathways for TE-PPE management. Prognostic stratification models were used to guide therapy by 4%. Indications for thrombolytic therapy varied considerably; 40% had a standardized protocol for thrombolysis, employing various modalities (45% systemic, 25% catheter-directed, 19% pharmaco-mechanical) and tissue plasminogen activator dose intensities. Duration of anticoagulation was variable with 58% prescribing anticoagulation for duration of >3 months-6 months; 61% followed for long-term adverse outcomes. CONCLUSION: This multinational survey of thrombosis/hemostasis specialists mainly based at pediatric academic centers demonstrates that antithrombotic management of TE-PPE (including duration of anticoagulation and use/non-use of thrombolysis) varies considerably. Furthermore, standardized care pathways to facilitate acute evaluation and management decisions are in place in a minority of centers. These findings help to inform the design of future clinical trials in TE-PPE.

The pediatric acenocoumarol dosing algorithm: the Children Anticoagulation and Pharmacogenetics Study.

Essentials A pediatric pharmacogenetic dosing algorithm for acenocoumarol has not yet been developed. We conducted a multicenter retrospective follow-up study in children in the Netherlands. Body surface area and indication explained 45.0% of the variability in dose requirement. Adding the genotypes of VKORC1, CYP2C9 and CYP2C18 to the algorithm increased this to 61.8%. SUMMARY: Background The large variability in dose requirement of vitamin K antagonists is well known. For warfarin, pediatric dosing algorithms have been developed to predict the correct dose for a patient; however, this is not the case for acenocoumarol. Objectives To develop dosing algorithms for pediatric patients receiving acenocoumarol with and without genetic information. Methods The Children Anticoagulation and Pharmacogenetics Study was designed as a multicenter retrospective follow-up study in Dutch anticoagulation clinics and children's hospitals. Pediatric patients who used acenocoumarol between 1995 and 2014 were selected for inclusion. Clinical information and saliva samples for genotyping of the genes encoding cytochrome P450 (CYP) 2C9, vitamin K epoxide reductase complex subunit 1 (VKORC1), CYP4F2, CYP2C18 and CYP3A4 were collected. Linear regression was used to analyze their association with the log mean stable dose. A stable period was defined as three or more consecutive International Normalized Ratio measurements within the therapeutic range over a period of ≥ 3 weeks. Results In total, 175 patients were included in the study, of whom 86 had a stable period and no missing clinical information (clinical cohort; median age 8.9 years, and 49% female). For 80 of these 86 patients, genetic information was also available (genetic cohort). The clinical algorithm, containing body surface area and indication, explained 45.0% of the variability in dose requirement of acenocoumarol. After addition of the VKORC1, CYP2C9, and CYP2C18 genotypes to the algorithm, this increased to 61.8%. Conclusions These findings show that clinical factors had the largest impact on the required dose of acenocoumarol in pediatric patients. Nevertheless, genetic factors, and especially VKORC1, also explained a significant part of the variability.

Characteristics and quality of oral anticoagulation treatment in pediatric patients in the Netherlands based on the CAPS cohort.

Essentials The knowledge of quality and safety of acenocoumarol and phenprocoumon use in children is limited. We used data from a multicenter retrospective follow-up study in children in the Netherlands. The quality of anticoagulation control in the first month of use was low, but improved thereafter. No thromboembolic events occurred, however bleeding events occurred in 1-3 out of 10 patients. SUMMARY: Background The use of vitamin-K antagonists in pediatric patients is rare and information on the quality and safety of treatment with acenocoumarol and phenprocoumon is limited. Objectives To assess the quality, safety and effectiveness during the first year of acenocoumarol and phenprocoumon treatment in pediatric patients in the Netherlands. Methods The Children Anticoagulation and Pharmacogenetics Study (CAPS) was designed as a multicenter retrospective follow-up study. Patients who used acenocoumarol or phenprocoumon at an age of ≤ 18 years, were selected from four pediatric hospitals and one anticoagulation clinic in the Netherlands. The quality of treatment was assessed by calculating the percentage of time in therapeutic INR range (TTR) for the first month and for every 3 months of use during the first year of treatment. Effectiveness and safety were assessed by the number of thromboembolic and bleeding events. Results In total, 213 patients participated, of whom 187 (155 acenocoumarol; 32 phenprocoumon) were included in this analysis. The mean TTR was 47.0% and 51.4% in the first month of use for acenocoumarol and phenprocoumon, respectively. After the first 3 months the mean TTR for both VKAs was above 64%. In 14.6% (acenocoumarol) and 31.3% (phenprocoumon) of the patients a bleeding event occurred during the first year of treatment; no thromboembolic events were reported. Conclusions The quality of anticoagulation treatment was low during the first month of use and leaves room for improvement. After the first month it increased to an acceptable level. However, bleeding events occurred frequently during the first year.

Accrual in supportive care trials in pediatric oncology, a challenge!

PURPOSE: Treatment protocols in pediatric oncology have historically known high accrual rates, up to 94 %. Accrual for supportive care studies on the other hand appears to be a challenge. The aim of this study was to search for reasons explaining this poor accrual and for possible interventions to improve patient enrolment. METHODS: The failure screen log of our supportive care study (the Aristocaths study) was analyzed, and subsequently, a literature search was performed. RESULTS: The literature search (1985-2011) revealed three factors that can influence accrual. Firstly, study implementation and patient enrolment can be facilitated by appointing a dedicated clinical investigator in all participating centers and by facilitating clinical research nurses. Furthermore, adequate and tailor-made information is required for families to make a well-informed decision regarding study participation. Lastly, sufficient time should be assured for the process of decision making, especially since the number of eligible studies is increasing rapidly. Concerning our study, all three elements were met, but the most striking finding was the presumed burden of study participation by the majority of parents (82 %) as the main argument against randomization. CONCLUSIONS: Accrual of pediatric oncology patients in supportive care studies is challenging. Nevertheless, well-designed randomized controlled trials in supportive care will be essential for the improvement of pediatric cancer care. Therefore, we will need to increase awareness through (inter)national supportive care working groups regarding the need for supportive care trials and stimulate accrual when such trials are open.

Prophylactic anticoagulation decreases catheter-related thrombosis and occlusion in children with home parenteral nutrition.

BACKGROUND: Home parenteral nutrition (PN) has improved the survival of children with intestinal failure. Important complications include catheter-related thrombosis, occlusion, and infection. This study evaluated the efficacy and safety of prophylactic anticoagulation in the prevention of these complications. METHODS: Medical records were retrospectively reviewed of all children (0-18 years) with PN between January 1994 and March 2007 in 1 tertiary center. After introduction of prophylactic low molecular weight heparin or vitamin K antagonists in March 2007, all patients were prospectively followed until March 2010. RESULTS: In sum, 14 patients did not receive prophylaxis; 13 switched from no prophylaxis to prophylaxis in March 2007; and 5 directly received prophylaxis. Median age of PN onset was 4 months (range, 0.1-202) in the nonprophylaxis group (n = 27) and 25 (range, 2-167) in the prophylaxis group (n = 18); 16 children received low molecular weight heparin and 2, vitamin K antagonists. Catheter-related thrombosis developed in 9 patients with no prophylaxis (33%) and 1 with prophylaxis (6%) (P = .034). Cumulative 5-year thrombosis-free survival was 48% and 93% in the nonprophylaxis and prophylaxis groups, respectively (P = .047). Per 1,000 PN days, the nonprophylaxis and prophylaxis groups had 2.6 and 0.1 occlusions (P = .04) and 4.6 and 2.1 infections (P = .06), respectively. Cumulative infection-free survival after 3 years was 19% and 46% in the nonprophylaxis and prophylaxis groups, respectively (P = .03). Bleeding complications did not occur. CONCLUSION: Thromboprophylaxis significantly decreased catheter-related thrombosis and occlusion in children with PN without complications.

Neonatal cerebral sinovenous thrombosis from symptom to outcome.

BACKGROUND AND PURPOSE: Cerebral sinovenous thrombosis is a rare disease with severe neurological sequelae. The aim of this retrospective multicenter study was to investigate the clinical course, possible risk factors, and outcome of a cohort of neonatal patients with sinovenous thrombosis and, second, to estimate the incidence in The Netherlands. METHODS: From January 1999 to March 2009, a review of all neonatal patients with sinovenous thrombosis from 6 tertiary neonatal intensive care units was performed. Population characteristics, clinical presentation, (prothrombotic) risk factors, neuroimaging, interventions, and neurodevelopment were evaluated. An estimated incidence was calculated based on the Netherlands Perinatal Registry. RESULTS: Fifty-two neonates were included (39 boys) with a median gestational age of 39 weeks (range, 30 to 42 weeks; 5 preterm). An assisted or complicated delivery occurred in 32 of 52. Presenting symptoms developed at a median postnatal age of 1.5 days (range, 0 to 28 days) and consisted mainly of seizures (29 of 52). All sinovenous thrombosis cases were confirmed with MRI/MR venography. Multisinus thrombosis was most common followed by superior sagittal sinus thrombosis. FII G20210A mutation was present in 2 of 18 tested neonates (11%). Anticoagulation therapy (in 22 of 52) did not result in hemorrhagic complications. At follow-up (median age, 19 months; range, 3 to 72 months), moderate to severe neurological sequelae were present in 38%. The mortality was 10 of 52 (19%). A variable, although high yearly incidence of 1.4 to 12 per 100 000 term newborns was found. CONCLUSIONS: Neonatal sinovenous thrombosis is a multifactorial disease. The estimated incidence in The Netherlands seems higher than reported elsewhere.

Etiology and treatment of perinatal stroke; a role for prothrombotic coagulation factors?

The detection rate of perinatal stroke is rising due to improved neuroradiological imaging techniques, increased survival of neonates with severe underlying diseases and an increased awareness of the diagnosis by pediatricians. Its pathogenesis is multifactorial and includes a large variety of maternal and neonatal risk factors as well as prothrombotic coagulation factors. Although the relative risk of prothrombotic coagulation factors is still unknown, testing is recommended to design large studies in the near future. This article is an overview of studies of prothrombotic risk factors in both neonatal arterial ischemic stroke and cerebral sinovenous thrombosis. Although prothrombotic coagulation factors are present in more than half of the cases, we conclude that they most likely play a minor role in the pathogenesis of perinatal stroke. Current therapeutic guidelines focusing on thrombosis are based on expert opinion and recommend low molecular weight or unfractionated heparin for cardioembolic arterial ischemic stroke, antiplatelet or anticoagulant therapy for recurrent arterial ischemic stroke, and low molecular weight heparin or unfractionated heparin for sinovenous thrombosis without hemorrhage and/or when extension of the thrombotic process occurs.

Intensive peri-operative use of factor VIII and the Arg593-->Cys mutation are risk factors for inhibitor development in mild/moderate hemophilia A.

BACKGROUND: A severe and challenging complication in the treatment of hemophilia A is the development of inhibiting antibodies (inhibitors) directed towards factor VIII (FVIII). Inhibitors aggravate bleeding complications, disabilities and costs. The etiology of inhibitor development is incompletely understood. OBJECTIVES: In a large cohort study in patients with mild/moderate hemophilia A we evaluated the role of genotype and intensive FVIII exposure in inhibitor development. PATIENTS/METHODS: Longitudinal clinical data from 138 mild/moderate hemophilia A patients were retrospectively collected from 1 January 1980 to 1 January 2008 and analyzed by multivariate analysis using Poisson regression. RESULTS: Genotyping demonstrated the Arg593Cys missense mutation in 52 (38%) patients; the remaining 86 patients had 26 other missense mutations. Sixty-three (46%) patients received intensive FVIII concentrate administration, 41 of them for surgery. Ten patients (7%) developed inhibitors, eight of them carrying the Arg593Cys mutation. Compared with the other patients, those with the Arg593Cys mutation had a 10-fold increased risk of developing inhibitors (RR 10; 95% CI, 0.9-119).The other two inhibitor patients had the newly detected mutations Pro1761Gln and Glu2228Asp. In both these patients and in five patients with genotype Arg593Cys, inhibitors developed after intensive peri-operative use of FVIII concentrate (RR 186; 95% CI, 25-1403). In five of the 10 inhibitor patients FVIII was administered by continuous infusion during surgery (RR 13; 95% CI, 1.9-86). CONCLUSION: The Arg593Cys genotype and intensive peri-operative use of FVIII, especially when administered by continuous infusion, are associated with an increased risk for inhibitor development in mild/moderate hemophilia A.

Pediatric venous thromboembolic disease in one single center: congenital prothrombotic disorders and the clinical outcome.

To learn more about the frequencies of congenital prothrombotic disorders in pediatric venous thromboembolism (VTE) and the outcome of this disease, we evaluated consecutive patients from 0 to 18 years with objectively diagnosed VTE at a single tertiary center over a 12-year period. We included 100 patients, with a median age at diagnosis of 1.0 year (range 2 days to 17 years). At least one underlying clinical condition was present in 96% of the patients. Factor (F)V G1691A mutation was present in 13%, FII G20210A mutation in 3%, antithrombin deficiency in 1%, protein C deficiency in 1% and protein S deficiency in 1% of the tested patients. Combined defects were present in 2.6% of the 77 patients with a complete work-up. Positive family history appeared to be the only predictor for positive testing for congenital disorders (OR 14.9, 95% CI 1.9-113). The overall mortality rate was 20%. The cumulative recurrence-free survival was 92% after 1 year of follow-up, and 82% after 7 years. The incidence and severity of the post-thrombotic syndrome was analyzed in a subgroup of 33 patients with VTE of the lower extremities. Twenty-three (70%) patients developed PTS: moderate in three and mild in 20 patients. In conclusion, congenital prothrombotic disorders seem to play a role in the development of pediatric VTE, and the risk of complications of this disease is high.

Venous thromboembolism in childhood: a prospective two-year registry in The Netherlands.

OBJECTIVE: To study the incidence, signs and symptoms, diagnostic tests, risk factors, therapy, and complications of pediatric venous thromboembolism (VTE) in The Netherlands. METHODS: A prospective 2-year registry of VTE in children aged < or = 18 years. RESULTS: Ninety-nine patients were registered. The annual incidence of VTE was 0.14/10,000 children, 35% of whom were symptom free. Almost half of the patients were newborns. Neonatal VTE was almost exclusively catheter related, located in the upper venous system, and asymptomatic. In older children VTE was catheter related in approximately one third and more often was located in the lower venous system. In 85% of all patients, thrombosis developed while the patient was in the hospital. Diagnosis was usually made by ultrasonography. In 98% of all patients, at least 1 risk factor was present. Congenital prothrombotic disorders were more often present in older children (21%) than in neonates (6%). A variety of treatment modalities were used. Morbidity consisted of bleeding (7%) and recurrent thrombosis (7%). Two children died as result of VTE. CONCLUSION: VTE is mostly diagnosed in hospitalized children, especially sick newborns with central venous catheters and older children with a combination of risk factors. Primary prevention, optimal treatment, and long-term outcome of pediatric symptomatic and asymptomatic VTE need to be studied.

Carbohydrate-deficient glycoprotein syndrome type 1a: a variant phenotype with borderline cognitive dysfunction, cerebellar hypoplasia, and coagulation disturbances.

An 8-year-old boy is described with borderline cognitive impairment, cerebellar hypoplasia, a stroke-like episode, and venous thrombosis of the left leg after a period of immobilization. The pattern of multiple abnormalities in blood coagulation suggested carbohydrate-deficient glycoprotein syndrome type 1a. Isoelectric focusing of serum transferrin was abnormal. The activity of phosphomannomutase in leukocytes and fibroblasts was decreased. Mutation analysis of the PMM2 gene revealed the R141H/E151G genotype. These results confirm the presence of carbohydrate-deficient glycoprotein syndrome type 1a without severe psychomotor retardation.

Acquired protein S deficiency caused by estrogen treatment of tall stature.

OBJECTIVE: To evaluate the potential thrombogenic changes in the coagulation and fibrinolytic system related to treatment with ethinyl estradiol (200 and 300 microg). SUBJECTS AND METHODS: Twenty-five healthy girls with expected final height exceeding 185 cm, as calculated by the method of Bayley and Pinneau, were treated with 200 microg or 300 microg of ethinyl estradiol. Coagulation and fibrinolytic parameters were determined before and during estrogen treatment and 2 and 4 weeks after estrogen withdrawal. RESULTS: No difference in the effects on hemostasis was found between the 2 treatment groups. All 25 patients developed protein S deficiency during estrogen treatment, which in most girls lasted for 4 weeks after cessation of estrogen administration. During therapy, protein C activity increased, whereas antithrombin did not change. Plasminogen and plasmin-alpha(2) antiplasmin complexes significantly increased. Protein S deficiency was accompanied by significantly increased prothrombin fragment 1+2 and fibrinopeptide A. In contrast, thrombin-antithrombin complexes did not change. CONCLUSION: High-dose estrogen treatment to reduce the final height in tall girls is associated with a reversible acquired protein S deficiency with indications of a pre-thrombotic state. Risk of venous thrombo-embolism may be enhanced, especially when additional risk factors for thrombosis are present.

Persistent tachypnea in children: keep pulmonary embolism in mind.

PURPOSE: Tachypnea in children is associated with respiratory disorders and nonrespiratory disorders such as cardiac disease, metabolic acidosis, fever, pain, and anxiety. Pulmonary embolism is seldom considered by pediatricians as a cause of tachypnea. PATIENTS AND METHODS: Three children of various ages with persistent tachypnea are described: a girl after orthopedic surgery for kyphoscoliosis, a boy with nephrotic syndrome, and a neonate with Hirschsprung disease. Other causes of tachypnea were diagnosed and treated before pulmonary embolism was considered. RESULTS: Ventilation-perfusion scanning appeared to be highly probable for pulmonary embolism in these patients. Anticoagulant therapy was started. CONCLUSION: Pulmonary embolism should be kept in mind in children with tachypnea, especially when other risk factors for venous thromboembolism are present, to avoid delay in anticoagulant treatment and a fatal outcome.