Elevated plasma factor VIII and D-dimer levels as predictors of poor outcomes of thrombosis in children

The role of coagulation factors VIII, IX and XI in the prediction and mediation of recurrent thrombotic events in children with non-central venous catheter deep vein thrombosis

BACKGROUND

The role of elevated coagulation factors VIII (FVIII), FIX, FXI for the prediction of recurrent thrombotic events in children after an index non-central venous catheter (non-CVC) related deep vein thrombosis (DVT) remains unclear.

OBJECTIVE

This study investigates the predictive role of FVIII, FIX, and FXI for recurrent thrombosis in children with index non-CVC DVTs, and the mediation effect of FVIII on chronic inflammation and recurrent thrombosis.

METHODS

Children aged 0-18 years diagnosed with an index non-CVC related DVT (1993-2020) were included in this single-center retrospective cohort study. Plasma levels of FVIII, FIX, FXI were measured cross-sectionally ≥30 days after the acute DVT. The association between the continuous variables FVIII, FIX, FXI and thrombosis recurrence was investigated using uni- and multivariable logistic regression, adjusting for age, sex, and chronic inflammation. Mediation analysis assessed the role of FVIII as a mediator between chronic inflammation and recurrent thrombosis. Ethics approval was obtained.

RESULTS

A total of 139 children with an index non-CVC related DVT were included. Thirty-eight (27 %) had a recurrent thrombosis at a median of 237 days (P25-P75 65-657 days) after the index DVT. In uni- and multivariable-analysis, FVIII, FIX or FXI did not predict thrombosis recurrence; However, chronic inflammation was an independent predictor. There was no evidence that FVIII mediated the effect of chronic inflammation on thrombosis recurrence.

CONCLUSION

We found no evidence that elevated FVIII, FIX or FXI predicted thrombosis recurrence, or evidence of a mediating role of FVIII. Underlying chronic inflammation predicted venous recurrent thrombotic events in this cohort.

Coagulation Profile in Neonates with Congenital Heart Disease: A Pilot Study

Background and Objectives: congenital heart disease (CHD), cyanotic and, to a lesser degree, acyanotic, often are accompanied by coagulation abnormalities, impacting substantially morbidity and mortality. Until now, no consistent hemostatic patterns have been demonstrated in neonates and children with CHD because they represent a variable and heterogenous population. The aim of the present study is to investigate the hemostatic profile, as well as the role of ADAMTS-13 (a disintegrin and metalloprotease with thrombospondin type-1 motives), the cleaving protein of von Willebrand factor (VWF) in neonates with CHD and compare them to healthy age-matched controls. Materials and Methods: twenty neonates with a mean gestational age of 37.1 ± 2.5 weeks were included in the CHD group, and 18 healthy neonates with a mean gestational age of 38.2 ± 1.5 weeks were in the control group. Results: prothrombin time was significantly prolonged, and accordingly, factor VII (FVII) levels were significantly decreased in the CHD group in comparison to controls. Factor VIII (FVIII), VWF, and ristocetin cofactor activity (Rcof) levels were significantly higher in the study vs. control group. Concentrations of ADAMTS-13 were decreased in the CHD vs. control group, but the difference was not statistically significant. Our results, in combination, indicate a balanced hemostatic mechanism, although with greater variability in neonates with CHD, while developmental aspects of coagulation are evident in the specific patient population. Conclusions: the coagulation profile is moderately impaired early in the course of CHD, though increased thrombogenicity is already present and should not be ignored.

Biomarkers in pediatric venous thromboembolism: a systematic review of the literature

BACKGROUND

Accurate prediction of the individual risk of venous thromboembolism (VTE) remains suboptimal in children, and biomarkers are currently not used to stratify the risk of VTE in children.

OBJECTIVES

This study aimed to assess which biological or radiological biomarkers may predict VTE or VTE complications in children.

PATIENTS/METHODS

A literature search was performed for peer-reviewed publications (1990-2022). We included studies addressing the use of biomarkers for patients aged 29 days to 18 years to predict VTE or its complications, including but not limited to TE-related death, VTE recurrence, or postthrombotic syndrome. Given the heterogeneity of the study designs, populations, and outcomes, no quantitative data synthesis was performed.

RESULTS

Forty studies were included, totaling 10,987 participants (median age: 4.7 years). Reports were often lacking critical methodological data, including blood collection method (68% of studies) and timepoints, laboratory testing technique (41%), or primary outcome definition (20%). Forty-six individual biomarkers were assessed for VTE prediction (32 studies, 9525 participants), including d-dimers, fibrinogen, platelet count, white blood cell count, and factor VIII. Albumin, C-reactive protein, d-dimers, factor VIII, and thrombin-antithrombin levels showed promising results for VTE prediction. In 9 studies (1606 participants), no biomarker was consistently predictive of postthrombotic syndrome, VTE persistence, or VTE recurrence in children.

CONCLUSIONS

Several candidate biomarkers were promising in the prediction of VTE in children. Still, discrepancies between different studies and the high risk of bias from the current literature prevent their widespread use in the clinical setting. Further prospective research in various pediatric subpopulations is required.

Prolonged Elevations of Factor VIII and von Willebrand Factor Antigen After Multisystem Inflammatory Syndrome in Children

Multisystem Inflammatory Syndrome in Children (MIS-C) is a late systemic inflammatory response to a recent mild or asymptomatic coronavirus disease of 2019 infection. The pathophysiology is incompletely understood but it often features significant coagulopathy along with cardiac and endothelial dysfunction. Endothelial inflammation has been primarily described in acute coronavirus disease of 2019 infection, with less characterization in MIS-C. Here we describe novel findings of nearly universal severe and prolonged factor VIII (FVIII) and von Willebrand factor antigen elevations in an institutional cohort of patients with MIS-C ages younger than or 21 years old (N=31). All patients had elevated acute phase reactants and D-dimer at presentation and met published criteria for MIS-C. FVIII was high at presentation in 97% of patients but continued to rise during the ensuing weeks of treatment to a mean 429%, peaking on median day 17 of illness as an outpatient. FVIII levels were >600% in multiple patients. von Willebrand factor antigen was measured less frequently but showed similar trends. These escalations occurred amidst resolving cardiac dysfunction and acute phase reactant normalization and despite patients receiving multimodal anti-inflammatory treatments and aspirin and enoxaparin thromboprophylaxis. No thrombotic events occurred. Endothelial dysfunction represented by very elevated FVIII levels may persist longer than other acute phase reactants may reflect.

Role of factor VIII, IX, and XI in venous thrombosis recurrence risk in adults and children: A systematic review

Background

Predicting recurrent venous thromboembolic events (VTEs) is challenging in clinical practice for both adults and children, but it is relevant for clinical management. Identifying laboratory risk factors for VTE recurrence may aid in clinical decision-making.

Objective

The goal of this systematic review is to investigate the predictive role of FVIII, IX, or XI in recurrent VTE in adult and pediatric patients with a first VTE.

Methods

A systematic review of the published literature was conducted in databases MEDLINE In-Process, Other Nonindexed Citations, MEDLINE Epub Ahead of Print, EMBASE Classic + EMBASE (OvidSP), and Cochrane (Wiley). We included observational and interventional studies that comprised adults or children with a first VTE, FVIII, FIX, and/or FXI and objectively confirmed VTE recurrence. The quality in prognosis studies tool was used to assess the risk of bias.

Results

We identified 2177 unique studies, of which 19 were included (18 for adults and 1 for children). The risk of bias was overall low to moderate. The studies were heterogenous with regards to population (provoked/unprovoked primary VTE), exposure (type of assay and cut-off values), and statistical analysis results (measures of association and modeling strategy). In adults, contradictory evidence was found for FVIII and FXI as outcome predictors, while no research could establish if FIX predicts VTE recurrence. Data in pediatrics were limited. Given the extensive heterogeneity of the literature, a meta-analysis was not performed.

Conclusions

Overall, there is contradictory evidence that FVIII, FIX, or FXI predict recurrent VTE in adults and children. Addressing heterogeneity is a relevant aspect to consider in future studies investigating prognostic factors for VTE recurrence.

Developing and optimizing a machine learning predictive model for post-thrombotic syndrome in a longitudinal cohort of patients with proximal deep venous thrombosis

BACKGROUND

Post-thrombotic syndrome (PTS) is the most common chronic complication of deep venous thrombosis (DVT). Risk measurement and stratification of PTS are crucial for patients with DVT. This study aimed to develop predictive models of PTS using machine learning for patients with proximal DVT.

METHODS

Herein, hospital inpatients from a DVT registry electronic health record database were randomly divided into a derivation and a validation set, and four predictive models were constructed using logistic regression, simple decision tree, eXtreme Gradient Boosting (XGBoost), and random forest (RF) algorithms. The presence of PTS was defined according to the Villalta scale. The areas under the receiver operating characteristic curves, decision-curve analysis, and calibration curves were applied to evaluate the performance of these models. The Shapley Additive exPlanations analysis was performed to explain the predictive models.

RESULTS

Among the 300 patients, 126 developed a PTS at 6 months after DVT. The RF model exhibited the best performance among the four models, with an area under the receiver operating characteristic curves of 0.891. The RF model demonstrated that Villalta score at admission, age, body mass index, and pain on calf compression were significant predictors for PTS, with accurate prediction at the individual level. The Shapley Additive exPlanations analysis suggested a nonlinear correlation between age and PTS, with two peak ages of onset at 50 and 70 years.

CONCLUSIONS

The current predictive model identified significant predictors and accurately predicted PTS for patients with proximal DVT. Moreover, the model demonstrated a nonlinear correlation between age and PTS, which might be valuable in risk measurement and stratification of PTS in patients with proximal DVT.

A prospective marker for the prediction of postoperative deep venous thrombosis: Neutrophil extracellular traps

Deep venous thrombosis (DVT) is a common medical complication in patients with lumbar fractures. The current study aimed to investigate the predictive value of neutrophil extracellular traps (NETs) in postoperative DVT formation in patients with lumbar fractures and to develop a nomogram relating clinical admission information for prediction. Patients who underwent open reduction and pedicle screw internal fixation in the treatment of single-segment lumbar fracture in the Department of Spine Surgery, the First Affiliated Hospital of Nanjing Medical University, from December 2020 to June 2022 were enrolled in this study. Baseline data and laboratory results were collected from enrollees, and the primary study endpoint event was the occurrence of DVT in patients after surgery. Multivariable logistic regression analysis was used to identify risk factors associated with higher odds of DVT after surgery. A nomogram was constructed using the results of the multivariable model. The calibration plot and receiver operating characteristics (ROC) curve were used to show the satisfactory predictive capacity of the model. Of these 393 patients who did not have DVT preoperatively, 79 patients developed it postoperatively, and 314 did not, respectively. Multivariate analysis showed that higher body mass index (BMI) (BMI between 24 and 28: RR = 1.661, 95% CI = 0.891-3.094; BMI ≤28: RR = 5.625, 95% CI = 2.590-12.217; reference: BMI <24), neutrophils (RR = 1.157, 95% CI 1.042-1.285), D-dimer (RR = 1.098, 95% CI 1.000-1.206), and citrullinated histone H3 (CitH3) (RR = 1.043, 95% CI 1.026-1.060) were independent risk factors for postoperative DVT. Using the multivariable analysis, we then constructed a nomogram to predict DVT, which was found to have an area under the curve of 0.757 (95% CI = 0.693-0.820). Calibration plots also showed the satisfied discrimination and calibration of the nomogram. In conclusion, patients with lumbar fractures with postoperative DVT had higher levels of NETs in the circulation preoperatively compared to those without postoperative DVT. Furthermore, based on BMI, D-dimer, neutrophils, and CitH3, we developed a predictive model to predict postoperative DVT incidence in these patients.

Effect of breathing intervention in patients with COVID and healthcare workers

Background

Regulated breathing facilitates ventilation and reduces breathlessness. However, the effect of Yogic breathing on patients with COVID remains unclear. We aimed to evaluate the efficacy of two breathing protocols, i.e., short breathing technique (SBT) and long duration breathing technique (LBDT).

Methods

Three groups including COVID-positive patients, COVID-recovered patients, and healthcare workers (HCWs) were included in the study and segregated into Yoga and control groups. SBT was administered to COVID-positive patients. Both SBT and LBDT were administered to COVID-recovered patients and HCWs. A total of 18 biochemical parameters, a 6-min walk test (6MWT), and a 1-min sit-stand test (1MSST) were assessed on 0th, 7th, and 15th days, where biochemical parameters were the primary outcome. Pre-post estimation of neuropsychological parameters (nine questionnaires) and heart rate variability (HRV) were carried out. The paired t-test or Wilcoxon rank test was applied for pre-post comparison and the Student's t-test or Mann-Whitney U test was used for group comparison. Repeated measures test was applied for data recorded at three time points.

Results

A significant elevation in white blood cell (WBC) count was observed in COVID-positive intervention (p < 0.001) and control groups (p = 0.003), indicating no role of intervention on change in WBC number. WBC count (p = 0.002) and D-dimer (p = 0.002) significantly decreased in the COVID-recovered intervention group. D-dimer was also reduced in HCWs practicing Yogic breathing as compared to controls (p = 0.01). D-dimer was the primary outcome, which remained below 0.50 μg/ml (a cutoff value to define severity) in the COVID-positive yoga group (CYG) and decreased in the COVID-recovered yoga group (RYG) and the HCW yoga group (HYG) after intervention. A 6-min walk test (6MWT) showed an increase in distance covered among the COVID-positive patients (p = 0.01) and HCWs (p = 0.002) after intervention. The high-frequency power (p = 0.01) was found to be reduced in the COVID-positive intervention group. No significant change in neuropsychological parameters was observed.

Conclusion

Yogic breathing lowered D-dimer, which is helpful in reducing thrombosis and venous thromboembolism in patients with COVID-19 besides lowering the chances of vaccine-induced thrombotic thrombocytopenia in vaccinated individuals. The breathing intervention improved exercise capacity in mild to moderate cases of COVID-19. Further studies can show if such breathing techniques can influence immunity-related genes, as reported recently in a study. We suggest that Yogic breathing may be considered an integrative approach for the management of patients with COVID.

Trial registration

http://ctri.nic.in/Clinicaltrials/login.php, identifier: CTRI/2020/10/028195.

Thrombin generation in children using ThromboScreen reagent kit with ST Genesia-A pilot study

INTRODUCTION

Thrombin generation assays assess overall coagulation system and are widely used in research; however, they still need standardization and clinical validation. The new ST Genesia is a benchtop, automated analyzer that normalizes each thrombin generation parameter using a reference plasma. The ThromboScreen reagent kit has two triggers, one of which contains thrombomodulin to assess the effect of the protein C pathway. This study aimed to make a pilot approach to the ThromboScreen reference range in children and evaluate the impact of sex, age, and pro- and anticoagulant plasma proteins on thrombin generation parameters.

METHODS

This study included 55 healthy children from the following age groups: 1-6 years (n = 14), 7-11 years (n = 15), and 12-17 years (n = 26). Children younger than 1 year were excluded from the study. We measured thrombin generation using ThromboScreen, coagulation routine and test, pro- and anticoagulant proteins.

RESULTS

Age did not influence ThromboScreen results. Males showed significantly lower endogenous thrombin potential and peak height values than females. The strongest determinants of endogenous thrombin potential were von Willebrand factor parameters, whereas for endogenous thrombin potential inhibition, the strongest determinants were protein C and protein S. No statistically significant differences were found between groups on temporal parameters.

CONCLUSIONS

For the ThromboScreen reagent kit, it may not be necessary to subdivide reference ranges according to age for children (>1 year).

The Level of D-Dimer Is Positively Correlated With the Severity of Mycoplasma pneumoniae Pneumonia in Children

Objective

Mycoplasma pneumoniae pneumonia (MPP) is an important disease in children. Studies have demonstrated that the levels of D-dimer are elevated in some children with MPP, especially those with thrombotic complications. However, the potential association between MPP and D-dimer remains unclear. In our study, we sought to explore the relationship between the levels of plasma D-dimer and clinical characteristics of MPP patients.

Methods

Retrospective analysis was conducted on 356 patients who were hospitalized in our hospital for MPP between January 1, 2017, and December 31, 2019. According to the peak value of D-dimer, patients were divided into three groups: the normal group (D-dimer<0.55 mg/L), the mild-moderately elevated group (D-dimer 0.55–5.5 mg/L) and the severely elevated group (D-dimer >5.5 mg/L). The demographic and clinical information, radiological findings, laboratory data, and treatments of patients were compared among different groups.

Results

106 patients were in the normal group, 204 patients were in the mild-moderately elevated group, and 46 patients were in the severely elevated group. More severe clinical and radiographic manifestations, longer length of fever, hospital stay and antibiotic therapy duration, higher incidences of extra-pulmonary complications, refractory MPP (RMPP), severe MPP (SMPP) were found in the elevated group, when compared with the normal group (P<0.01). Meanwhile, we found that the percentage of neutrophil (N%) and CD₈⁺ lymphocyte (CD₈⁺%), C-reactive protein (CRP), lactate dehydrogenase (LDH), interleukin (IL)-6, IL-10, and interferon-gamma (IFN-γ) trended higher with increasing D-dimer, whereas the percentage of lymphocyte (L%) and prealbumin (PAB) trended lower (P<0.01). In addition, the proportions of patients requiring oxygen therapy, glucocorticoid, bronchoscopy, immunoglobulin use, thoracentesis, or ICU admission were significantly higher in the severely elevated group than those in the other two groups (P<0.01). Correlation analysis showed that N%, L%, CRP, LDH, IL-10, length of fever, length of stay, and length of antibiotic therapy had strong correlations with the level of D-dimer.

Conclusions

MPP patients with higher levels of D-dimer had more severe clinical manifestations and needed longer duration of treatment, which might be closely related to the severity of lung inflammation after MP infection.

A Real-time Risk-Prediction Model for Pediatric Venous Thromboembolic Events

BACKGROUND

Hospital-associated venous thromboembolism (HA-VTE) is an increasing cause of morbidity in pediatric populations, yet identification of high-risk patients remains challenging. General pediatric models have been derived from case-control studies, but few have been validated. We developed and validated a predictive model for pediatric HA-VTE using a large, retrospective cohort.

METHODS

The derivation cohort included 111 352 admissions to Monroe Carell Jr. Children's Hospital at Vanderbilt. Potential variables were identified a priori, and corresponding data were extracted. Logistic regression was used to estimate the association of potential risk factors with development of HA-VTE. Variable inclusion in the model was based on univariate analysis, availability in routine medical records, and clinician expertise. The model was validated by using a separate cohort with 44 138 admissions.

RESULTS

A total of 815 encounters were identified with HA-VTE in the derivation cohort. Variables strongly associated with HA-VTE include history of thrombosis (odds ratio [OR] 8.7; 95% confidence interval [CI] 6.6-11.3; P < .01), presence of a central line (OR 4.9; 95% CI 4.0-5.8; P < .01), and patients with cardiology conditions (OR 4.0; 95% CI 3.3-4.8; P < .01). Eleven variables were included, which yielded excellent discriminatory ability in both the derivation cohort (concordance statistic = 0.908) and the validation cohort (concordance statistic = 0.904).

CONCLUSIONS

We created and validated a risk-prediction model that identifies pediatric patients at risk for HA-VTE development. We anticipate early identification of high-risk patients will increase prophylactic interventions and decrease the incidence of pediatric HA-VTE.

Plasma fibrinolysis, inflammatory markers, and postthrombotic syndrome: preliminary findings from the Kids-DOTT Biobank

Plasma levels of markers of coagulation and inflammation have been identified as prognostic factors for adult postthrombotic syndrome (PTS). We aimed to determine whether plasma fibrinolytic capacity and cytokine levels during the first 3 months after provoked deep venous thrombosis (DVT) are associated with risk of PTS in young patients. We analyzed plasma biospecimens (6 weeks and 3 months after provoked DVT) and clinical data from a National Heart, Lung, and Blood Institute-sponsored multinational trial of anticoagulation for provoked venous thromboembolism in patients younger than age 21 years (Kids-DOTT). Patients with a provoked extremity DVT who had plasma samples available at both 6-week and 3-month post-DVT time points and PTS assessment at 1 year were included. We measured plasma fibrinolytic capacity using the Clot Formation and Lysis (CloFAL) assay and plasma cytokine levels by multiplex immunoassay. Logistic regression analyses evaluated prognostic associations with PTS. Seventy-nine patients were included (median age, 12.8 years; range, 0.04-20.8 years). PTS developed in 34%. Complete veno-occlusion at 6 weeks after diagnosis of DVT (odds ratio [OR], 3.12; 95% confidence interval [CI], 0.81-11.94; P = .097), low fibrinolytic capacity in plasma at 3 months post-DVT (OR, 2.71; 95% CI, 0.92-7.97; P = .07), and elevated serum amyloid A at 3 months post-DVT (OR, 2.85; 95% CI, 0.98-8.34; P = .055) were identified as putative prognostic factors for development of PTS. In multivariable logistic regression analysis, these factors did not retain a statistically significant independent association with PTS, but these preliminary results warrant further investigation in an independent data set to definitively evaluate these findings and identify additional potential prognostic factors for the development of PTS after a provoked DVT in young patients.

Pediatric May-Thurner Syndrome-Systematic review and individual patient data meta-analysis

BACKGROUND

The outcomes of deep vein thrombosis (DVT) in children with May-Thurner Syndrome (MTS) remain unclear.

OBJECTIVES

This systematic review and patient-level meta-analysis aims to describe the outcomes of children with MTS presenting with DVT.

METHODS

A systematic review of the published literature was performed. Data related to patients <18 years diagnosed with MTS and DVT was extracted. Risk of bias was assessed using the Murad criteria. Outcomes included vessel patency post-treatment, DVT recurrence, and post-thrombotic syndrome (PTS). Predictive and explanatory models were developed for these outcomes.

RESULTS

In total, 109 cases were identified (age range 4-17 years; 77 females) in 28 studies; 75% of patients had ≥1 additional risk factor for DVT. PTS was seen in 61% of patients, DVT recurrence in 38%, and complete vessel patency post-treatment in 65%. The models developed to predict and explain PTS performed poorly overall. Recurrent thrombosis (adjusted for age and patency) predicted PTS (odds ratio [OR] 3.36, 95% confidence interval [CI] 1.28-8.82). DVT management strategies (adjusted for age and DVT characteristics) predicted vessel patency (OR 2.10, 95% CI 1.43-3.08). Lack of complete vessel patency (adjusted for age and thrombophilia) predicted recurrent DVT (OR 2.70, 95% CI 1.09-6.67). Sensitivity analyses showed the same direction of effects for all outcomes.

CONCLUSIONS

PTS and DVT recurrence occur frequently in pediatric MTS. PTS prediction is complex and it was not possible to identify early predictors to guide clinical practice. Use of imaging-guided therapy and thrombus burden predicted venous patency, and lack of patency predicted DVT recurrence.

Antithrombin deficiency: A pediatric disorder

INTRODUCTION

Hereditary antithrombin (AT) deficiency is an autosomal dominant thrombophilic disorder. Guidelines do not support routine testing of children based on personal or familial thrombosis.

AIM

To investigate clinical, genetic and laboratory profiles of AT deficient children and their affected family members.

MATERIALS AND METHODS

Data were analyzed from a prospective cohort of pediatric patients with AT deficiency. The SERPINC1 gene was sequenced for all individuals with available DNA. AT, thromboelastography (TEG), calibrated automated thrombogram (CAT), D-dimer, thrombin-antithrombin complex (TAT) and factor VIII activity were performed on patient samples.

RESULTS

Thirty-six individuals from 11 families had AT deficiency (activities 45-70 U/dL) with incident thrombosis in 13 children and 10 adults (64% overall). Three neonates presented with middle cerebral artery and/or aortic occlusions with inferior vena cava and cerebral or renal vein thromboses in 2 of the 3. Two pre-pubertal children were symptomatic, one with cerebral venous sinus thrombosis who suffered recurrent arterial and venous thrombi. Both Type I and Type II AT deficiencies conferred a high severity of thromboses. Heterozygous SERPINC1 mutations were identified in seven families; three were novel, resulting in missense, splice site and frameshift alterations. Thrombin generation (CAT) was increased in all asymptomatic affected patients including 9 children and 1 adult.

CONCLUSIONS

Genetic AT deficiency often presents in infants and children, warranting laboratory evaluation based on personal and family history. Increased thrombin generation was detected in all asymptomatic children and adults, suggesting a possible role in detecting and monitoring individuals at risk for thrombosis.

Elevated factor VIII levels and arterial stroke: a review of literature with a case report

Background

Cerebral arterial thromboses or ischemic strokes may be caused by cumulative or independent effects of a variety of risk factors. High factor VIII level is one of those important but less known risk factors for arterial and venous thrombosis. We hereby provide a comprehensive review of the role of high factor VIII levels as a risk factor of arterial thrombosis. Moreover, we present our views on inclusion of factor VIII testing in the etiology workup protocol of young patients with ischemic strokes and their treatment with anticoagulant therapy.

Case presentation

We illustrate a case of 32-year-old North Indian female patient with Ischemic stroke whose only identifiable risk factor was revealed to be an elevated factor VIII level. She was treated with oral anticoagulant with an uneventful follow-up of 6 months.

Conclusions

Elevated factor VIII levels have their independent and additive effects in causation and prognosis of arterial strokes. We herein discuss the mechanism of this association, the feasibility and yield of routine testing, appropriate cut-off levels, and further treatment protocol especially in young stroke patients.

Predictors of postthrombotic syndrome in pediatric thrombosis: A systematic review and meta-analysis of the literature

BACKGROUND

Postthrombotic syndrome (PTS) is a significant complication of pediatric deep venous thrombosis (DVT). There is a gap in the understanding of the risk factors associated with the development of pediatric PTS preventing the early identification of those patients at greatest risk, and the development of risk-stratified interventions.

OBJECTIVES

To conduct a systematic review and meta-analysis of the literature on prognostic factors for PTS development in pediatric patients.

METHODS

A systematic search of MEDLINE, EMBASE, and the Cochrane Library from 1960 to December 2018 was performed. Eligible studies reported at least one prognostic factor for PTS development in patients < 21 years of age with a radiographically confirmed DVT. To be included in the meta-analysis, prognostic factors had to be reported in at least three published studies.

RESULTS AND CONCLUSIONS

Twelve studies (n = 1160 patients) met criteria for inclusion. Ninety-three percent of patients with an extremity DVT (n = 1076) were assessed for PTS. PTS developed in 40% (n = 434) of these patients. Central venous catheter-associated DVT (odds ratio [OR], 1.8; 95% confidence interval [CI], 1.08-2.98), complete veno-occlusion (OR, 1.89; 95% CI, 1.04-3.46), and incomplete DVT resolution (OR, 2.07; 95% CI, 1.4-3.07) were identified as candidate prognostic factors for pediatric PTS. These findings should be interpreted in the context of the heterogeneity of the included studies and the limitations of current pediatric PTS assessment tools. Further, the predictive value of these prognostic factors will need to be validated in future collaborative prospective multicenter studies that maximize the homogeneity of pediatric DVT patients.

Risk factors for pediatric cerebral sinovenous thrombosis: A case-control study with case validation

INTRODUCTION

Cerebral sinovenous thrombosis (CSVT) represents the second most common type of venous thromboembolism (VTE) in children. Current literature includes limited evidence on risk factors for CSVT, particularly in the pediatric population. We sought to determine risk factors for CSVT in pediatric patients through a single-institutional case-control study. In addition, we evaluated thrombophilias, treatments and outcomes in CSVT among cases.

METHODS

A case-control study was performed at Johns Hopkins All Children's Hospital on patients admitted from March 31, 2006 through April 1, 2018. Cases were identified using diagnostic codes and confirmed based on electronic health record (EHR) and neuroimaging review. Controls were matched in a 2:1 fashion accounting for the month and year of admission.

RESULTS

A total of 60 CSVT cases and 120 controls were identified. Median (range) age was 4.8 years (0-21.3 years) for cases and 5.6 years (0-20.0 years) for controls. Factors putatively associated with CSVT in unadjusted analyses were: corticosteroid use, presence of a central venous catheter, mechanical ventilation, systemic infection, head/neck infection, head/neck trauma, and chronic inflammatory disease. In the multivariable model, head/neck infection (OR: 13.8, 95% CI: 4.87-38.7; P < 0.01), head/neck trauma (OR: 12.7, 95% CI: 2.88-56.2; P < 0.01), and mechanical ventilation (OR: 9.32, 95% CI: 2.35-36.9; P = 0.01) remained independent, statistically-significant risk factors. 61% of patients were subacutely treated with anticoagulants and of those, only two developed relevant bleeding after initiation of therapy.

CONCLUSIONS

This single-institutional case-control study reveals that head/neck infection, head/neck trauma, and mechanical ventilation are independent risk factors for pediatric CSVT. These findings will be further investigated via a cooperative registry of pediatric hospital-acquired VTE, by which a risk model for pediatric CSVT will be developed and validated, in order to inform future preventive strategies in at-risk pediatric patients.

In Children with Provoked Venous Thromboembolism, Increasing Plasma Coagulability during the First 3 Months Postdiagnosis is Prognostic of Recurrence

Prognostic factors for venous thromboembolism (VTE) recurrence following provoked VTE are largely unknown. Using the Clot Formation and Lysis (CloFAL) assay, single institutional research has shown overall improvement in acute hypercoagulability during the first 3 months postpediatric VTE, yet a rise in plasma coagulability in a subgroup of patients. We sought to define the incidence of rise in coagulability during the first 3 months post-provoked VTE, to investigate its relationship with elevated D-dimer, and to test the hypothesis that a marked rise in coagulability is independently prognostic of VTE recurrence. CloFAL and D-dimer assays were performed on plasma at 4 to 6 weeks and 3 months post-VTE in the Johns Hopkins pediatric VTE cohort and National Institutes of Health-sponsored Kids-DOTT trial. Associations of VTE recurrence with D-dimer and CloFAL assay measures were evaluated via logistic regression. Eighty-seven patients were included. Median follow-up was 1 year. Complete veno-occlusion was determined in 12% at 6 weeks. During the first 3 months post-VTE, a marked rise in coagulability was observed by CloFAL assay in 17% of patients, while D-dimer was elevated in 21%. Recurrent VTE occurred in 10% of patients. CloFAL assay, but not D-dimer, was associated with recurrence (odds ratio [OR] 5.87, 95% confidence interval [95% CI], 1.34-25.8]). After adjustment for veno-occlusion, patients with a marked rise in coagulability by CloFAL assay had a 10-fold increased risk of recurrent VTE (OR 10.33 [95% CI, 1.83-58.19]). Future work should seek to elucidate the mechanisms underlying a rise in plasma coagulability following provoked VTE and to substantiate its prognostic utility for recurrent VTE.

A bibliometric analysis of publications on venous thromboembolism in children from 1988 to 2019

INTRODUCTION

Venous thromboembolism (VTE) in children not only imposes a heavy burden on the medical resources and economy of the society, but also seriously affects the growth and development of children, even threaten children's lives. A large number of publications have been performed in this field in recent years. In this bibliometric analysis, publications on VTE in children were examined and analyzed to explain the present research hotspots.

METHODS

Articles related to VTE in children published in the PubMed database from 1988 to June 18, 2019 were selected as the research sample. BICOMB software was used to retrieve the annual publications, journals, journal source countries and the high-frequency major medical subject headings (MeSH) terms on the articles. Then, the co-word matrix was constructed by BICOMB using the selected high-frequency MeSH terms. Next, gCLUTO software was used to analyze the matrix by double clustering and visual analysis in a strategy of hotspot identification. In addition, CiteSpace software was used to perform the knowledge map of co-authors to explore the core authors.

RESULTS

One thousand seven hundred seventy-nine articles on VTE in children were obtained. Seven hundred ninety academic journals distributed in 58 countries have published articles on VTE in children, and the developed countries and the United States were the major force in the journal source countries. Nowak-Göttl U occupied an important position in this field. We constructed a co-word matrix composing of 37 high-frequency MeSH terms, generated visual matrix and visual hill, and classified the hot-spots into 5 aspects based on 8 categories.

CONCLUSION

The results show that the research trend of children's VTE has been increasing gradually, and the sound achievement has been obtained in these hotspots in relation to the area of inherited thrombophilia, prevention and control, treatment, diagnosis, prevalence, risk factors, and complication study. However, there is a lack of communication and cooperation in this field, and the gap of national and regional research results is huge. To sum up, this study provides evidence and guidance for researchers, clinicians, and educators.

The role of thrombophilia genes in the clinical implementation of arterial and venous thrombosis in newborns

The article considers the analysis results of the occurrence frequency of genotypes and alleles of plasma, platelet and fibrinolytic hemostasis in full-term newborns with arterial and venous thrombosis of various localization. Gene polymorphisms were studied by real-time PCR in human DNA samples obtained from buccal epithelium and venous blood lymphocytes. The control group was a group of healthy full-term newborns from families without a thrombophilic history. Predictors of arterial and venous thrombosis in children are such as polymorphism of the plasminogen activator inhibitor gene PAI-1-675 4G/4G (OR=5,6 [2,3-13,8]), combinations of polymorphisms PAI-1-675 4G/4G + factor VII G10976A G/G (OR=5,8 [1,7-19,1]), combinations of polymorphisms PAI-1 -675 4G/4G + factor VII G10976A G/G + factor XIII Val34Leu G/G (% AR=61), fibrinogen FGB -455 G/A (OR=3,75 [1,4-9,4]) and integrin alpha 2 ITGA2 807 T/T (OR=15,56 [1,9-126,7]). Thus, the study of polymorphisms of the plasminogen activator inhibitor, fibrinogen, integrin alpha 2 can serve as one of the criteria for identifying a high-risk group for the development of arterial and venous thrombosis in newborns and should be taken into account when evaluating individual thrombophilia risk.

The Impact of Multiple Risk Factors for Venous Thromboembolism and Its Implications for Management

Venous thromboembolism (VTE) is a rare multifactorial disorder in childhood with an annual incidence of about 0.07 to 0.14 per 10 000 children. A 15-year-old female with a body mass index of 48 kg/m² who endorsed oral contraceptive use presented with clinical findings consistent with deep venous thrombosis along with the presence of a pulmonary embolism. Further workup revealed that the patient was heterozygous for factor V Leiden and homozygous for prothrombin G20210A mutations. There are no current pediatric guidelines for the antithrombotic management of patients with multiple risk factors for VTE. Two such risk factors, obesity and the use of estrogen-containing hormone contraceptives, have been implicated in adult VTE cases but have not been clearly delineated in pediatric patients. The need for guidance regarding the VTE management of these patients has become more apparent given the increasing incidence of childhood obesity and the number of adolescents using oral contraceptives. Additionally, thrombophilia testing remains controversial though testing may be indicated in asymptomatic first-degree relatives and in families with antithrombin, protein C, or protein S deficiencies. Given the increased incidence of multiple risk factors for VTE, there is also a need to develop a comprehensive risk assessment tool for pediatric patients at high risk of VTE.

Thrombosis in Children: Approach to Anatomic Risks, Thrombophilia, Prevention, and Treatment

Pediatric venous thromboembolism (VTE) is increasing in incidence but minimal data exist for best practices regarding therapy, use of thrombophilia testing, and management of long-term complications. Classification schema use anatomic location and presence of clinical or thrombophilic inciting factors. There are a small number of risk-assessment and risk-modeling systems for incident VTE, but all suffer from low numbers, single-institution design, and lack of prospective validation. Acute treatment is limited to heparin products and thrombolysis may be indicated in specific situations. In addition, chronic postthrombotic comorbidities are expected to increase in incidence and lack evidence-based treatment paradigms.

A prediction model for successful anticoagulation in cirrhotic portal vein thrombosis

BACKGROUND AND OBJECTIVE

Portal vein thrombosis (PVT) is a common complication in cirrhosis, and when complete, it increases morbidity and mortality in liver transplant candidates. The aim of the study was to assess the hemostatic status, as well as clinical characteristics of thrombus and patients, as predictors of therapeutic efficacy of anticoagulation for the treatment of PVT in cirrhotics.

PATIENTS AND METHODS

Patients with cirrhosis consecutively treated for PVT with enoxaparin were enrolled. All patients underwent evaluation of coagulation status and thrombophilia screening. Thrombus characteristics and extension were evaluated at baseline and during follow-up. Anticoagulation was continued until recanalization or up to 12 months. Variables correlated with the response to anticoagulation were used to create a predictive score that was validated in an external multicenter cohort.

RESULTS

A total of 65 patients were included and had partial PVT in most cases (72%). Treatment with enoxaparin resulted in an overall response rate of 66% (43/65) after a median time of 4.4 months and 76% (33/43) within the first 6 months. At multivariate analysis, efficacy of anticoagulation correlated with the severity of liver disease, complete verus partial PVT, age of the thrombus, and time interval from treatment start (<6 months). The areas under the curve of the statistical model for predicting the response to anticoagulation were 0.84 and 0.76 for the training (n=65) and validation (n=60) cohorts, respectively.

CONCLUSION

Early diagnosis and early treatment are key factors for the successful management of PVT in cirrhosis, so that screening of PVT and prompt start of anticoagulant treatment should be mandatory.

The natural history of asymptomatic central venous catheter-related thrombosis in critically ill children

Asymptomatic central venous catheter (CVC)-related thrombosis in children varies in incidence from 5% to 69%. The rate of acute and long-term complications, such as postthrombotic syndrome (PTS), from asymptomatic CVC-related thrombosis is unknown. This article reports the outcomes of a prospective study of 189 children in pediatric intensive care that aimed to determine the frequency of asymptomatic CVC-related thrombosis during hospital admission, and the incidence of residual CVC-related thrombosis and clinically significant PTS 2 years later. Risk factors associated with CVC-related thrombosis were also identified. This study is distinct from previous work as children identified to have asymptomatic CVC-related thrombosis were not treated (clinical team kept blinded) and the entire cohort was followed for 2 years to determine the natural history of asymptomatic thrombosis. Ultrasounds of 146 children determined a 21.9% incidence of acute CVC-related thrombosis. Two children were symptomatic. No radiological thrombosis extension or clinical embolization occurred in the 126 children assessed at follow-up. Using 2 recognized PTS scales, clinically significant PTS was reported in 2 children (1 symptomatic, 1 asymptomatic CVC-related thrombosis), however, neither had functional impairment. Cardiac arrest was a risk factor for CVC-related thrombosis during admission and femoral CVC placement was predictive of residual thrombosis 2 years later. This study challenges the notion that critically ill children with asymptomatic CVC-related thrombosis require anticoagulant treatment, as the results demonstrate that the incidence of acute or long-term complications is low. A larger confirmatory study of nontreatment of CVC-related thrombosis in critically ill children is justified.

Biomarkers of disseminated intravascular coagulation in pediatric intensive care unit in Thailand

INTRODUCTION

Disseminated intravascular coagulation (DIC) is a systemic activation of hemostatic system caused by several causes. Biomarkers including antithrombin (AT), protein C (PC), and thrombomodulin (TM) were reported as the additional markers for DIC in adults. This study aimed to determine the association between biomarkers among patients with overt DIC (ODIC) and nonovert DIC (NDIC) in children in PICU.

METHODS

We enrolled 103 subjects, aged 1 month-18 years, who were admitted to PICU at Chiang Mai University (CMU) Hospital >24 hours with underlying conditions predisposing to DIC were enrolled. Biomarkers were tested after 24 hours of admission. Subject who had NDIC on the 1^st investigations would have other tests on days 3-5 of admission.

RESULTS

The incidence of ODIC by the International Society on Thrombosis and Hemostasis (ISTH) DIC score was found 24%. The bleeding, thrombosis, and death were significantly higher in ODIC group (P < 0.05). Mean levels of AT and PC in ODIC group were significantly different from NDIC one (66.9% vs 79.9%, P < 0.001 and 46.1% vs 59.2%, P = 0.004, respectively) while mean level of TM was not different between two groups. Adding AT to DIC score was better than the original score for predict mortality [area under curve (AUC) = 0.662 vs AUC = 0.65] and bleeding (AUC = 0.751 vs AUC = 0.732).

CONCLUSIONS

ODIC is prevalent among critically ill children. Adverse outcomes were more commonly found in children with ODIC. AT and PC levels after 24 hours of PICU admission seem to be the useful biomarkers for ODIC in PICU.

Thrombophilia testing in children: What and when should be tested?

Venous thrombosis (VTE) in children is gaining increased awareness and apart from underlying medical conditions, recently reported systematic reviews on pediatric VTE (70% provoked) have shown significant associations between thrombosis and presence of inherited thrombophilic risk factors (IT), such as protein C-, protein S- and antithrombin deficiency, mutations of factor 5 (F5: rs6025) and factor 2 (F2: rs1799963), even more pronounced when combined IT were involved. Although we have learned more about the pathophysiology of VTE with the increased discovery of IT evidence is still lacking as to whether IT influence the clinical outcome in pediatric VTE. It still remains controversial as to whether children with VTE or offspring from thrombosis-prone families benefit from IT screening. Thus, IT testing in children should be individualized. If the decision "pro screening" is discussed as an appropriate option in adolescents with unprovoked VTE and in children with a positive family history for VTE screening should be performed in a specialized coagulation unit for acquired or inherited and prothrombotic defects based on the individual population background. Apart from the laboratory assessment for the presence/absence of lupus anticoagulants and antiphospholipid antibodies screening should be performed beyond the acute VTE onset and after withdrawal of anticoagulant medication possibly influencing laboratory results.

Risk factors for hospital-associated venous thromboembolism in critically ill children following cardiothoracic surgery or therapeutic cardiac catheterisation

BACKGROUND

Paediatric hospital-associated venous thromboembolism is a leading quality and safety concern at children's hospitals.

OBJECTIVE

The aim of this study was to determine risk factors for hospital-associated venous thromboembolism in critically ill children following cardiothoracic surgery or therapeutic cardiac catheterisation.

METHODS

We conducted a retrospective, case-control study of children admitted to the cardiovascular intensive care unit at Johns Hopkins All Children's Hospital (St. Petersburg, Florida, United States of America) from 2006 to 2013. Hospital-associated venous thromboembolism cases were identified based on ICD-9 discharge codes and validated using radiological record review. We randomly selected two contemporaneous cardiovascular intensive care unit controls without hospital-associated venous thromboembolism for each hospital-associated venous thromboembolism case, and limited the study population to patients who had undergone cardiothoracic surgery or therapeutic cardiac catheterisation. Odds ratios and 95% confidence intervals for associations between putative risk factors and hospital-associated venous thromboembolism were determined using univariate and multivariate logistic regression.

RESULTS

Among 2718 admissions to the cardiovascular intensive care unit during the study period, 65 met the criteria for hospital-associated venous thromboembolism (occurrence rate, 2%). Restriction to cases and controls having undergone the procedures of interest yielded a final study population of 57 hospital-associated venous thromboembolism cases and 76 controls. In a multiple logistic regression model, major infection (odds ratio=5.77, 95% confidence interval=1.06-31.4), age ⩽1 year (odds ratio=6.75, 95% confidence interval=1.13-160), and central venous catheterisation (odds ratio=7.36, 95% confidence interval=1.13-47.8) were found to be statistically significant independent risk factors for hospital-associated venous thromboembolism in these children. Patients with all three factors had a markedly increased post-test probability of having hospital-associated venous thromboembolism.

CONCLUSION

Major infection, infancy, and central venous catheterisation are independent risk factors for hospital-associated venous thromboembolism in critically ill children following cardiothoracic surgery or cardiac catheter-based intervention, which, in combination, define a high-risk group for hospital-associated venous thromboembolism.

Duration of anticoagulant therapy in pediatric venous thromboembolism: Current approaches and updates from randomized controlled trials

INTRODUCTION

Compared with the incidence of venous thromboembolism in the adult population, pediatric VTE is rare. Yet, recent data suggest that the incidence of VTE in children is increasing, and little is known about the optimal duration of anticoagulation in pediatrics. Areas covered: This review summarizes current evidence-based adult recommendations and associated clinical trials from which current guidelines on the duration of anticoagulation in children have been extrapolated. It also discusses pediatric expert consensus-based guidelines and current pediatric clinical trials on duration of therapy in pediatric VTE. Expert commentary: The vast majority of pediatric VTE are provoked, and evidence on duration of anticoagulation for pediatric VTE is highly limited, but suggests that a maximum duration of 3 months is reasonable for most patients with provoked VTE, whereas longer duration is likely appropriate for unprovoked VTE. Whether shorter duration than 3 months is optimal for pediatric provoked VTE is as yet unclear. Results from the multinational randomized controlled trial studying the duration of anticoagulant therapy for provoked VTE in patients <21 years old (Kids-DOTT) will be critical to inform the future standard of care in pediatric VTE treatment.

Markers of coagulation activation, inflammation and fibrinolysis as predictors of poor outcomes after pediatric venous thromboembolism: A systematic review and meta-analysis

BACKGROUND

Sequelae of venous thromboembolism (VTE) in children include recurrence, development of post thrombotic syndrome (PTS) when venous return from a limb is affected and chronic thromboembolic pulmonary hypertension (CTEPH) after pulmonary embolism. Identification of laboratory-based risk factors may be useful for individualized risk assessment for VTE sequelae. Coagulation activation and inflammation may contribute to their pathophysiology. We performed a systematic review to investigate the association between biomarkers of coagulation activation, inflammation and fibrinolysis and adverse VTE outcomes in children and young adults.

METHODS

A systematic search of electronic databases, PubMed (NIH), EMBASE (Ovid), Web of Science (Thompson Reuters), and SCOPUS (Elsevier) for studies published through November 2016 was conducted using "VTE" including MeSH terms for "coagulation activation," "inflammation" and "fibrinolysis," with no limit on publication date. A study was eligible for inclusion when it evaluated patients (< 21years) with VTE and biomarkers of coagulation activation, inflammation, and fibrinolysis and assessed for their association with development of adverse thrombotic outcomes. A modified Newcastle Ottawa Scale was applied to examine the quality of included studies.

RESULTS

Our search strategy yielded 200 references. A total of 3 cohort studies representing 220 patients with VTE were included. Two authors independently assessed all references for inclusion. Three studies (2 prospective cohort and one mixed cohort study) were identified that reported on biomarkers of coagulation activation, inflammation and fibrinolysis, checked at least once after VTE diagnosis and assessed association with primary outcomes of recurrent VTE, PTS and CTEPH. Studies varied with regards to definition of outcomes, the type of biomarkers measured and time point of measurement. We were unable to meta-analyze results due to marked clinical heterogeneity and <3 studies available for each biomarker. Descriptively, a significant association was found for elevated plasma levels of FVIII and D-dimer for a compound outcome of PTS, recurrence and progression in one study, and positive lupus anticoagulant at DVT diagnosis and subsequent PTS by another study. No studies were found for CTEPH.

CONCLUSIONS

Elevated D-dimer, FVIII and lupus anticoagulant show promise for predicting recurrent VTE and PTS in children and young adults. Further research is needed to elucidate whether these markers might be useful to predict development of adverse outcomes after VTE in children.

Six Weeks Versus 3 Months of Anticoagulant Treatment for Pediatric Central Venous Catheter-related Venous Thromboembolism

OBJECTIVE

Central venous catheters (CVCs) are the single most important predisposing factor for the development of pediatric venous thromboembolism (VTE). Treatment recommendations suggest anticoagulation for the duration of 6 weeks to 3 months. This project investigated clinical outcomes associated with 6 weeks compared with 3 months of enoxaparin therapy following diagnosis of a CVC-related VTE.

METHODS

This retrospective cohort study enrolled patients aged 18 years and below treated with enoxaparin with/without unfractionated heparin for a radiologically confirmed CVC-related VTE. Patients were identified using the pharmacy database, radiologic imaging, and medical records. Patients were divided into 2 groups based on the duration of anticoagulation (6+1 or 12±2 wk) and data were analyzed using descriptive statistics.

RESULTS

Seventy-four patients were included. Higher rates of complete thrombosis resolution were observed in children treated for 6 weeks at treatment cessation (39.4%) and long-term follow-up (61.5%), compared with 3 months (11.8% and 9.0%, respectively).

CONCLUSIONS

Six weeks of treatment for CVC-related VTE may provide noninferior clinical outcomes compared with 3 months of anticoagulation. An international randomized-controlled trial (Kids-DOTT) is underway to explore the optimal duration of anticoagulation for acute-provoked VTE in children. This manuscript highlights that data from such studies is urgently needed.

Novel perspectives on diagnosis and clinical significance of the post-thrombotic syndrome in children

INTRODUCTION

Given the increase in venous thromboembolic events (VTE) in children, the incidence, diagnosis and management of post thrombotic syndrome (PTS) in children is of increasing interest. Current challenges facing clinicians caring for children with VTE is the limited evidence of the long-term outcomes for this cohort; specifically the significance and potential functional impairment associated with PTS.

AREAS COVERED

This paper reviews the current evidence to elucidate the risk factors for PTS in children, methods for diagnosis and management of PTS in children (aged less than 18 years). Medline, Cinahl and PsycINFO database searches were undertaken using key search terms. Priority areas in need of further research are highlighted. Expert commentary: The two paediatric PTS assessment tools currently in use have been acknowledged to overcall the incidence of mild PTS in children. A PTS tool's ability to distinguish between clinically significant PTS and mild PTS is crucial. Variation in how PTS has been reported in children across the literature suggests that the real incidence of moderate and /or clinically significant PTS in children is unknown. Furthermore, evidence is lacking about the functional impairment experienced by children with clinically significant PTS and what this means for their long-term health.

How We Manage Pediatric Deep Venous Thrombosis

Over the past two decades, the incidence and recognition of venous thromboembolism (VTE) in children has significantly increased, likely as a result of improvements in the medical care of critically ill patients and increased awareness of thrombotic complications among medical providers. Current recommendations for the management of VTE in children are largely based on data from pediatric registries and observational studies, or extrapolated from adult data. The scarcity of high-quality evidence-based recommendations has resulted in marked variations in the management of pediatric VTE among providers. The purpose of this article is to summarize our institutional approach for the management of VTE in children based on available evidence, guidelines, and clinical practice considerations. Therapeutic strategies reviewed in this article include the use of conventional anticoagulants, parenteral targeted anticoagulants, new direct oral anticoagulants, thrombolysis, and mechanical approaches for the management of pediatric VTE.

Post thrombotic syndrome following deep vein thrombosis in paediatric patients

Background Although well characterised in adults, less is known about post-thrombotic syndrome in children. In this review, current knowledge regarding paediatric post-thrombotic syndrome is summarised, with particular emphasis on pathophysiology, aetiology, diagnosis and management. Methods A Medline literature review was performed using search terms 'post thrombotic syndrome', 'post phlebitic syndrome', paediatric and children. Relevant articles were identified and included for summation analysis. Results The incident of paediatric venous thromboembolism is rising. Deep vein thrombosis can cause venous hypertension through a combination of venous reflux, venous obstruction and impairment of the calf muscle pump, leading to development of post-thrombotic syndrome. In children, this is more likely to occur if deep vein thrombosis diagnosis and treatment are delayed, if a higher number of vessels are involved, and if factors such as D-dimer are elevated at diagnosis and throughout treatment. Post-thrombotic syndrome occurs in about 26% of paediatric deep vein thrombosis, though the results of individual studies vary widely. A number of tools exist to diagnose paediatric post-thrombotic syndrome, including the modified Villalta scale and Manco-Johnson instrument. Once post-thrombotic syndrome develops, the mainstay of treatment remains supportive, with little evidence of benefit from pharmacological measures. Conclusion Surgical or interventional treatment is not advised except in exceptional cirumstances, due to variable prognosis of PTS in paediatric populations with rising incidence of paediatric venous thromboembolism, it follows that the prevalence of post-thrombotic syndrome in children may also increase. Evidence-based venous thromboembolism prevention strategies need to be implemented for prevention of deep vein thrombosis, but when it does occur, deep vein thrombosis requires prompt and effective treatment to prevent post-thrombotic syndrome. Optimum treatment strategies for post-thrombotic syndrome require further investigation.

Pediatric Hospital Acquired Venous Thromboembolism

Pediatric hospital acquired venous thromboembolism (HA-VTE) is an increasing problem with an estimated increase from 5.3 events per 10,000 pediatric hospital admissions in the early 1990s to a current estimate of 30-58 events per 10,000 pediatric hospital admissions. Pediatric HA-VTE is associated with significant morbidity and mortality. The etiology is multifactorial but central venous catheters remain the predominant risk factor. Additional HA-VTE risk factors include both acquired (recent surgery, immobility, inflammation, and critical illness) and inherited risk factors. Questions remain regarding the most effective method to assess for HA-VTE risk in hospitalized pediatric patients and what preventative strategies should be implemented. While several risk-assessment models have been published in pediatric patients, these studies have limited power due to small sample size and require prospective validation. Potential thromboprophylactic measures include mechanical and pharmacologic methods both of which have associated harms, the most significant of which is bleeding from anticoagulation. Standard anticoagulation options in pediatric patients currently include unfractionated heparin, low molecular weight heparin, or warfarin all of which pose a monitoring burden. Ongoing pediatric studies with direct oral anticoagulants could potentially revolutionize the prevention and treatment of pediatric thrombosis with the possibility of a convenient route of administration and no requirement for monitoring. Further studies assessing clinical outcomes of venous thromboembolism (VTE) prevention strategies are critical to evaluate the effectiveness and harm of prophylactic interventions in children. Despite HA-VTE prevention efforts, thrombotic events can still occur, and it is important that clinicians have a high clinical suspicion to ensure prompt diagnosis and treatment to prevent further associated harms.

Advancing non-invasive neuromodulation clinical trials in children: Lessons from perinatal stroke

Applications of non-invasive brain stimulation including therapeutic neuromodulation are expanding at an alarming rate. Increasingly established scientific principles, including directional modulation of well-informed cortical targets, are advancing clinical trial development. However, high levels of disease burden coupled with zealous enthusiasm may be getting ahead of rational research and evidence. Experience is limited in the developing brain where additional issues must be considered. Properly designed and meticulously executed clinical trials are essential and required to advance and optimize the potential of non-invasive neuromodulation without risking the well-being of children and families. Perinatal stroke causes most hemiplegic cerebral palsy and, as a focal injury of defined timing in an otherwise healthy brain, is an ideal human model of developmental plasticity. Advanced models of how the motor systems of young brains develop following early stroke are affording novel windows of opportunity for neuromodulation clinical trials, possibly directing neuroplasticity toward better outcomes. Reviewing the principles of clinical trial design relevant to neuromodulation and using perinatal stroke as a model, this article reviews the current and future issues of advancing such trials in children.

Lemierre Syndrome: A Retrospective Study of the Role of Anticoagulation and Thrombosis Outcomes

Lemierre syndrome (LS) is a multisystemic infection beginning in the oropharynx and leading to thrombosis of the internal jugular vein (IJV) with septic emboli and potential thrombotic extension to the central nervous system. Although patient outcomes have improved with early initiation of antimicrobial therapies, there is no consensus regarding the role of anticoagulation in LS. To better define the role of anticoagulation therapy in LS and determine whether anticoagulation improves thrombosis outcomes, we conducted a retrospective chart review of pediatric and adult patients diagnosed with LS and managed at our institution from January 1998 to December 2014. Eighteen patients (9 females and 9 males) were included in this analysis, 6 of whom received ≥4 weeks of anticoagulation therapy (median 23.1 weeks, range 6.9-32.9 weeks). Six patients were in the pediatric age group (<18 years). All patients received broad-spectrum antibiotics. All patients had improvement in their thrombi by 3 months (nonanticoagulated patient group: complete response [CR], n = 9; partial response [PR], n = 3; anticoagulated patient group: CR, n = 2; PR, n = 4). No patient developed recurrent thrombosis or progression during the follow-up period, regardless of anticoagulation status. Our study suggests that anticoagulation in LS may not affect thrombosis outcomes.

Risk factors for symptomatic venous and arterial thromboembolism in newborns, children and adolescents - What did we learn within the last 20years?

Venous thrombosis (VTE) in children is increasingly diagnosed, as advanced medical care has increased treatment intensity of hospitalized pediatric patients. The aim of this review was to summarize the data available and to discuss the controversial issue of thrombophilia screening in the light of the pediatric data available. Follow-up data for VTE recurrence in children suggest a recurrence rate between 3% (neonates) and 21% in individuals with unprovoked VTE. Apart from underlying medical conditions, recently reported systematic reviews on pediatric VTE (70% provoked) have shown significant associations between thrombosis and presence of protein C-, protein S- and antithrombin deficiency, factor 5 (F5: rs6025), factor 2 (F2: rs1799963), even more pronounced when combined inherited thrombophilias [IT] were involved. The F2 mutation, protein C-, protein S-, and antithrombin deficiency did also play a significant role at VTE recurrence. Although we have learned more about the pathophysiology of VTE with the increased discovery of IT evidence is still lacking as to whether IT influence the clinical outcome in pediatric VTE. It still remains controversial as to whether children with VTE or offspring from thrombosis-prone families benefit from IT screening. Thus, IT testing in children should be individualized.

Current Practice of Pharmacological Thromboprophylaxis for Prevention of Venous Thromboembolism in Hospitalized Children: A Survey of Pediatric Hemostasis and Thrombosis Experts in North America

Pharmacological thromboprophylaxis (pTP) is the most effective intervention to prevent venous thromboembolism (VTE) in hospitalized adults. High-quality studies investigating the role of pTP in children are lacking. The aim of this study is to understand pediatric hematologists' current practices of pTP prescription and to explore their opinion about universal adoption of pTP for high-risk hospitalized children. An electronic survey was sent to members of Hemostasis and Thrombosis Research Society of North America. The response rate was 47.3% (53/112). VTE was perceived as a major hospital acquired complication by all and 96% (51/53) prescribed pTP in select cases. Majority would consider prescribing pTP for personal history of thrombosis, inheritance of severe thrombophilic conditions, and teen age. The majority of respondents (55%, 29/53) were either not in support of or uncertain about the universal adoption of pTP policy for high-risk hospitalized children. In total, 62% of respondents (33/53) did not support the use of pTP for central venous lines. Respondents reported on the presence of pharmacological (32%, 17/53) and mechanical (45%, 24/53) thromboprophylaxis policies at their institutions. Pediatric hematologists considered pTP a useful intervention to prevent VTE and prescribed pTP in select cases. Universal adoption of pTP was not supported. Wide variability in clinical practice was observed.

Plasma levels of D-dimer in a 5-year-old girl with systemic juvenile idiopathic arthritis: A case report and literature review

The present study reported high levels of D-dimer associated with multiple joint pain in a 5-year-old patient with systemic juvenile idiopathic arthritis (JIA). While treatment with methotrexate (MTX), hydroxychloroquine and methylprednisolone was found to reduce the D-dimer level and alleviated joint pain, the fever was not effectively controlled. Addition of etanercept to the treatment regimen from week 2 resulted in a clinical remission. Following 4-6 months of therapy, the D-dimer level of the patient returned to the normal range, and symptoms of noticeable joint pain and fever were absent. A literature search showed that the levels of D-dimer may be associated with JIA disease severity, and can serve as a prognostic biomarker for JIA treatment. In conclusion, the present study demonstrated that, while MTX therapy effectively reduced D-dimer levels, addition of etanercept to the treatment regimen was required to achieve a long-lasting remission of clinical symptoms, including fever.

Anticoagulants in children and adolescents

Thrombotic complications are increasing at a steady and significant rate in children, resulting in the more widespread use of anticoagulation in this population. Anticoagulant drugs in children can be divided into the older multitargeted agents (heparin, low-molecular-weight heparin, and warfarin) and the newer targeted agents (argatroban, bivalirudin, and fondaparinux). This review will compare and contrast the multitargeted and targeted anticoagulants and suggest situations in which it may be appropriate to use argatroban, bivalirudin, and fondaparinux. The various agents differ in their pharmacokinetics, requirements for therapeutic drug monitoring, frequency of administration, efficacy, and adverse effects. The targeted anticoagulants have properties that may make them more attractive for use in specific clinical situations. Prospective clinical trial data are presented supporting the current and future use of these agents in children.