Trends in venous thromboembolism-related hospitalizations, 1994-2009

Catheter-related deep vein thrombosis: Where are we at and where are we going? Updates and ongoing unmet clinical needs

BACKGROUND

Catheter-related thrombosis (CRT) is one of the major complications affecting patients with indwelling venous catheters, usually involving the upper extremity deep venous system. This condition can lead to potentially life-threatening complications such as pulmonary embolism and sepsis. The risk of developing CRT varies depending on type of catheters and patient characteristics. Despite advances in materials and technologies, the actual incidence of CRT is still considerable. Available evidence on CRT management remains controversial, and clinical guidelines base their recommendations on data from non-catheter related upper extremity or lower extremity deep venous thromboses.

AIMS

This narrative review aims to describe the epidemiology of CRT, to review the available evidence on its management and to highlight the current unmet needs.

METHODS

No formal search strategy was applied for the revision of the literature. The main sources of information used were Medline and guidelines from international societies.

CONTENT

The management of CRT requires a careful balance between the risk of thrombus progression, recurrent events, and systemic embolization and the increased bleeding risk in often fragile patients. Open issues include the optimal management of the catheter and the type and duration of anticoagulant therapy. Direct oral anticoagulants are increasingly prescribed, representing an important alternative to the standard of care low molecular weight heparins in selected cases. The development of new anticoagulant drugs such as factors XI and XII inhibitors may offer further advantages in this context.

CONCLUSIONS

The management of CRT is still challenging with constant need for updated evidence to support tailored approaches.

Incidence and risk factors for postthrombotic syndrome in neonates and children in a single-center cohort study

BACKGROUND

Postthrombotic syndrome (PTS) is a chronic condition following deep vein thrombosis (DVT) and is associated with pain, swelling, and restricted use of the affected limb. In pediatric age groups, its incidence and risk factors are not well-known.

METHODS

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

RESULTS

In total, 315 patients were included. The 20-year incidence of PTS was 20.0% in neonates and 40.0% in children. In neonates, involvement of ≥3 vessels (odds ratio [OR], 6.6; 95% CI, 1.6-26.4) and incomplete thrombus resolution (OR, 3.0; 95% CI, 1.1-8.0) were risk factors for PTS. In children, involvement of ≥3 vessels (OR, 6.2; 95% CI, 2.2-17.8), recurrent DVT (OR, 3.7; 95% CI, 1.3-10.3), and incomplete thrombus resolution (OR, 5.2; 95% CI, 1.6-17.0) were associated with PTS. Exercise ≥3 times/wk (OR, 0.4; 95% CI, 0.2-0.9), central venous catheter-related DVT (OR, 0.2; 95% CI, 0.1-0.5), and provoked DVT (OR, 0.4; 95% CI, 0.1-0.97) were protective factors for PTS.

CONCLUSION

This study demonstrated a high incidence of pediatric PTS. Additionally, risk factors for PTS differed between neonates and children. These findings provide a basis for better prevention and management of PTS that may differ between neonates and children.

Risk factors and incidence of central venous access device-related thrombosis in hospitalized children: a systematic review and meta-analysis

BACKGROUND

The risk factors for central venous access device-related thrombosis (CRT) in children are not fully understood. We used evidence-based medicine to find the risk factors for CRT by pooling current studies reporting risk factors of CRT, aiming to guide clinical diagnosis and treatment.

METHODS

A systematic search of PubMed, Web of Science, Embase, Cochrane Library, Scopus, CNKI, Sinomed, and Wanfang databases was conducted. RevMan 5.4 was employed for data analysis.

RESULTS

The review included 47 studies evaluating 262,587 children with CVAD placement. Qualitative synthesis and quantitative meta-analysis identified D-dimer, location of insertion, type of catheter, number of lumens, catheter indwelling time, and central line-associated bloodstream infection as the most critical risk factors for CRT. Primarily due to observational design, the quality of evidence was regarded as low certainty for these risk factors according to the GRADE approach.

CONCLUSION

Because fewer high-quality studies are available, larger sample sizes and well-designed prospective studies are still needed to clarify the risk factors affecting CRT. In the future, developing pediatric-specific CRT risk assessment tools is important. Appropriate stratified preventive strategies for CRT according to risk assessment level will help improve clinical efficiency, avoid the occurrence of CRT, and alleviate unnecessary suffering of children.

IMPACT

This is the latest systematic review of risk factors and incidence of CRT in children. A total of 47 studies involving 262,587 patients were included in our meta-analysis, according to which the pooled prevalence of CRT was 9.1%. This study identified several of the most critical risk factors affecting CRT in children, including D-dimer, insertion location, type of catheter, number of lumens, catheter indwelling time, and central line-associated bloodstream infection (CLABSI).

Published trends and research hotspots of central venous catheter-associated thrombosis from 1973 to 2022: A scientometric analysis

This study aims to explore the intellectual landscape and research hotspots in the central venous catheter-related thrombosis (CVC-RT) research field. Studies discussing CVC-RT published from 1973 to 2022 in the Web of Science Core Collection database were retrieved on February 24th, 2022. Citespace was used to perform a scientometric analysis to identify the intellectual landscape and research hotspots in the research fields of CVC-RT. A total of 4358 studies were retrieved, with an ascending trend in publication numbers. The United States of America was the most influential country. The Journal of Vascular Access published the most studies, and McMaster University was the most prolific institution. The results showed that the focus population of CVC-RT research has changed from pediatric patients to cancer patients, the management of CVC-RT has become more formal and standardized, and the focused CVC type has shifted to port and peripherally inserted central catheters. In addition, seventeen active burst keywords were detected, such as patient safety, clinical practice guidelines, and postthrombotic syndrome. This study comprehensively reviewed publications related to CVC-RT. The research topics on patient safety, clinical practice guidelines, and postthrombotic syndrome related to CVC-RT may be future hotspots.

Prenatal and Neonatal Pulmonary Thrombosis as a Potential Complication of SARS-CoV-2 Infection in Late Pregnancy

Neonatal venous thrombosis is a rare condition that can be iatrogenic or occur due to viral infections or genetic mutations. Thromboembolic complications are also commonly observed as a result of SARS-CoV-2 infections. They can affect pediatric patients, especially the ones suffering from multisystem inflammatory syndrome in children (MIS-C) or multisystem inflammatory syndrome in neonates (MIS-N). The question remains whether the maternal SARS-CoV-2 infection during pregnancy can lead to thromboembolic complications in fetuses and neonates. We report on a patient born with an embolism in the arterial duct, left pulmonary artery, and pulmonary trunk, who presented several characteristic features of MIS-N, suspecting that the cause might have been the maternal SARS-CoV2 infection in late pregnancy. Multiple genetic and laboratory tests were performed. The neonate presented only with a positive result of IgG antibodies against SARS-CoV-2. He was treated with low molecular weight heparin. Subsequent echocardiographic tests showed that the embolism dissolved. More research is necessary to evaluate the possible neonatal complications of maternal SARS-CoV-2 infection.

Risk of venous thromboembolism in pediatric hospitalized patients undergoing noncardiac surgery: A report from the Children's Hospital-Acquired Thrombosis consortium

Background

Surgery is a known risk factor for hospital-acquired venous thromboembolism (HA-VTE) in children.

Objectives

To assess whether the odds of HA-VTE differs across six anatomic sites of noncardiac surgery and to identify risk factors for HA-VTE in these children.

Methods

This was a multicenter, case-control study. Anatomic sites of surgery and risk factors for HA-VTE were collected on hospitalized pediatric patients who had undergone a single noncardiac surgery and developed HA-VTE (cases), and those who did not develop HA-VTE (controls), via the Children's Hospital-Acquired Thrombosis (CHAT) Registry. Logistic regression estimated the odds ratio (OR) and 95% confidence intervals (CIs) between six anatomic sites of surgery and 16 putative HA-VTE risk factors. Variables with a p value of 0.10 or less in unadjusted analyses were included in adjusted models for further evaluation. The final model used backward selection, with a significance level of 0.05.

Results

From January 2012 to March 2020, 163 cases (median age, 5.7 years; interquartile range [IQR], 0.3-14.2) and 208 controls (median age of 7.5 years; IQR, 3.7-12.9) met our criteria. There was no statistically significant increased odds of VTE among the types of noncardiac surgery. In the final adjusted model, central venous catheter (CVC; OR, 14.69; 95% CI, 7.06-30.55), intensive care unit (ICU) stay (OR, 5.31; 95% CI, 2.53-11.16), and hospitalization in the month preceding surgery (OR, 2.75; 95% CI, 1.24-6.13) were each independently significant risk factors for HA-VTE.

Conclusion

In children undergoing noncardiac surgery, placement of CVCs, admission/transfer to the ICU, or hospitalization in the month prior to surgery were positively associated with HA-VTE.

Risk factors for central venous catheter-associated deep venous thrombosis in pediatric critical care settings identified by fusion model

Background

An increase in the incidence of central venous catheter (CVC)-related thrombosis (CRT) has been reported in pediatric intensive care patients over the past decade. Risk factors for the development of CRT are not well understood, especially in children. The study objective was to identify potential clinical risk factors associated with CRT with novel fusion machine learning models.

Methods

Patients aged 0–18 who were admitted to intensive care units from December 2015 to December 2018 and underwent at least one CVC placement were included. Two fusion model approaches (stacking and blending) were used to build a better performance model based on three widely used machine learning models (logistic regression, random forest and gradient boosting decision tree). High-impact risk factors were identified based on their contribution in both fusion artificial intelligence models.

Results

A total of 478 factors of 3871 patients and 3927 lines were used to build fusion models, one of which achieved quite satisfactory performance (AUC = 0.82, recall = 0.85, accuracy = 0.65) in 5-fold cross validation. A total of 11 risk factors were identified based on their independent contributions to the two fusion models. Some risk factors, such as D-dimer, thrombin time, blood acid-base balance-related factors, dehydrating agents, lymphocytes and basophils were identified or confirmed to play an important role in CRT in children.

Conclusions

The fusion model, which achieves better performance in CRT prediction, can better understand the risk factors for CRT and provide potential biomarkers and measures for thromboprophylaxis in pediatric intensive care settings.

Supplementary information

The online version contains supplementary material available at 10.1186/s12959-022-00378-y.

Predictors of venous thromboembolism among infants in children's hospitals in the United States: a retrospective Pediatric Health Information Study

OBJECTIVES

Examine: (1) Prevalence of diagnosed venous thromboembolism (VTE) in infants <6 months discharged from U.S. NICUs; (2) Associations between sociodemographic and clinical factors and VTE; (3) Secondary outcomes related to VTE.

STUDY DESIGN

Multivariable logistic regressions examined associations between VTE and sociodemographic and clinical factors among infants <6 months discharged from Pediatric Health Information System (PHIS) NICUs between 2016 and 2019.

RESULTS

Of 201,033 infants, 2720 (1.35%) had diagnosed VTE. Birthweight 300-1000 g (aOR 3.14, 95% CI 2.54-3.88), 1000-1500 g (aOR 1.77, 95% CI 1.40-2.42) versus 2500-3999 g, and public (aOR 1.18, 95% CI 1.02-1.37) versus private insurance were associated with increased odds of VTE, as were CVC, TPN, mechanical ventilation, infection, ECMO, and surgery. All types of central lines (non-tunneled and tunneled CVCs, PICCs, and umbilical catheters) had higher odds of VTE than not having that type of line. CVCs in upper versus lower extremities had higher odds of VTE.

CONCLUSION

Infants with risk factors may require monitoring for VTE. Results may inform VTE prevention.

Thrombosis Complications in Pediatric Acute Lymphoblastic Leukemia: Risk Factors, Management, and Prevention: Is There Any Role for Pharmacologic Prophylaxis?

Pediatric acute lymphoblastic leukemia (ALL) has achieved close to 90% cure rates through extensive collaborative and integrative molecular research, clinical studies, and advances in supportive care. Despite this high achievement, venous thromboembolic complications (VTE) remain one of the most common and potentially preventable therapy-associated adverse events in ALL. The majority of thromboses events involve the upper central venous system which is related to the use and location of central venous catheters (CVC). The reported rates of symptomatic and asymptomatic CVC-related VTE range from 2.6 to 36.7% and 5.9 to 43%, respectively. Thrombosis can negatively impact not only disease-free survival [e.g., therapy delays and/or interruption, omission of chemotherapy agents (e.g., asparaginase therapy)] but also can result in long-term adverse effects that can impair the quality of life of ALL survivors (e.g., post-thrombotic syndrome, central nervous system (CNS)-thrombosis related complications: seizures, neurocognitive deficits). In this review, will discuss thrombosis pathophysiology in pediatric ALL, risk factors, treatment, and prevention strategies. In addition, the recently published clinical efficacy and safety of direct oral anticoagulants (DOACs) use in thrombosis treatment, and their potential role in primary/secondary thrombosis prevention in pediatric patients with ALL will be discussed. Future clinical trials involving the use of these novel oral anticoagulants should be studied in ALL not only for primary thrombosis prevention but also in the treatment of thrombosis and its secondary prevention. These future research findings could potentially extrapolate to VTE prevention strategies in other pediatric cancer diagnoses and children considered at high risk for VTE.

Association of venous thromboembolism following pediatric traumatic spinal injuries with injury severity and longer hospital stays

OBJECTIVE

Venous thromboembolism (VTE) can cause significant morbidity and mortality in hospitalized patients, and may disproportionately occur in patients with limited mobility following spinal trauma. The authors aimed to characterize the epidemiology and clinical predictors of VTE in pediatric patients following traumatic spinal injuries (TSIs).

METHODS

The authors conducted a retrospective cohort analysis of children who experienced TSI, including spinal fractures and spinal cord injuries, encoded within the National Trauma Data Bank from 2011 to 2014.

RESULTS

Of the 22,752 pediatric patients with TSI, 192 (0.8%) experienced VTE during initial hospitalization. Proportionally, more patients in the VTE group (77%) than in the non-VTE group (68%) presented following a motor vehicle accident. Patients developing VTE had greater odds of presenting with moderate (adjusted odds ratio [aOR] 2.6, 95% confidence interval [CI] 1.4-4.8) or severe Glasgow Coma Scale scores (aOR 4.3, 95% CI 3.0-6.1), epidural hematoma (aOR 2.8, 95% CI 1.4-5.7), and concomitant abdominal (aOR 2.4, 95% CI 1.8-3.3) and/or lower extremity (aOR 1.5, 95% CI 1.1-2.0) injuries. They also had greater odds of being obese (aOR 2.9, 95% CI 1.6-5.5). Neither cervical, thoracic, nor lumbar spine injuries were significantly associated with VTE. However, involvement of more than one spinal level was predictive of VTE (aOR 1.3, 95% CI 1.0-1.7). Spinal cord injury at any level was also significantly associated with developing VTE (aOR 2.5, 95% CI 1.8-3.5). Patients with VTE stayed in the hospital an adjusted average of 19 days longer than non-VTE patients. They also had greater odds of discharge to a rehabilitative facility or home with rehabilitative services (aOR 2.6, 95% CI 1.8-3.6).

CONCLUSIONS

VTE occurs in a low percentage of hospitalized pediatric patients with TSI. Injury severity is broadly associated with increased odds of developing VTE; specific risk factors include concomitant injuries such as cranial epidural hematoma, spinal cord injury, and lower extremity injury. Patients with VTE also require hospital-based and rehabilitative care at greater rates than other patients with TSI.

Prediction of central venous catheter-associated deep venous thrombosis in pediatric critical care settings

BACKGROUND

An increase in the incidence of central venous catheter (CVC)-associated deep venous thrombosis (CADVT) has been reported in pediatric patients over the past decade. At the same time, current screening guidelines for venous thromboembolism risk have low sensitivity for CADVT in hospitalized children. This study utilized a multimodal deep learning model to predict CADVT before it occurs.

METHODS

Children who were admitted to intensive care units (ICUs) between December 2015 and December 2018 and with CVC placement at least 3 days were included. The variables analyzed included demographic characteristics, clinical conditions, laboratory test results, vital signs and medications. A multimodal deep learning (MMDL) model that can handle temporal data using long short-term memory (LSTM) and gated recurrent units (GRUs) was proposed for this prediction task. Four benchmark machine learning models, logistic regression (LR), random forest (RF), gradient boosting decision tree (GBDT) and a published cutting edge MMDL, were used to compare and evaluate the models with a fivefold cross-validation approach. Accuracy, recall, area under the ROC curve (AUC), and average precision (AP) were used to evaluate the discrimination of each model at three time points (24 h, 48 h and 72 h) before CADVT occurred. Brier score and Spiegelhalter's z test were used measure the calibration of these prediction models.

RESULTS

A total of 1830 patients were included in this study, and approximately 15% developed CADVT. In the CADVT prediction task, the model proposed in this paper significantly outperforms both traditional machine learning models and existing multimodal deep learning models at all 3 time points. It achieved 77% accuracy and 90% recall at 24 h before CADVT was discovered. It can be used to accurately predict the occurrence of CADVT 72 h in advance with an accuracy of greater than 75%, a recall of more than 87%, and an AUC value of 0.82.

CONCLUSION

In this study, a machine learning method was successfully established to predict CADVT in advance. These findings demonstrate that artificial intelligence (AI) could provide measures for thromboprophylaxis in a pediatric intensive care setting.

Effectiveness and Safety of Nadroparin Therapy in Preterm and Term Neonates with Venous Thromboembolism

INTRODUCTION

Optimal neonatal nadroparin dosages to treat venous thromboembolism (VTE) are unknown.

OBJECTIVE

To evaluate therapeutic nadroparin dosages to reach therapeutic target ranges (TTR: 0.5-1.0 International Unit (IU)/mL) and the effectiveness and safety of nadroparin in neonatal VTE.

METHODS

Retrospective study including neonates with VTE on nadroparin in a tertiary center between 2007 and 2018. Two groups were distinguished: neonates before (group 1) and after (group 2) switch to higher starting dosages in 2014.

RESULTS

Sixty-one neonates (44 preterm, 17 term) with 64 VTEs were included. TTR was reached in 32/64 (50%) VTEs (group 1: 35.7%; group 2: 61.1%). Median nadroparin dosage to reach TTR was 197 (97.9-330.3) IU/kg/12 h. No therapy-related deaths occurred. Recurrent VTE developed in 6 (9.8%) neonates. Complete clot resolution was observed in 31/41 (75.6%) VTEs. TTR was reached in 58.1% VTEs with complete clot resolution. No major bleeding occurred. Non-major clinically relevant bleedings occurred in 3/64 (4.7%) VTEs, consisting of large hematomas due to the use of subcutaneous catheters.

CONCLUSIONS

High nadroparin dosages are needed to reach TTR in neonates, which seem to be safe. Clot resolution may occur without reaching TTR. Subcutaneous catheters may cause important bleeding complications.

Adult Donor Blood Products as Risk Factors for Central Venous Catheter-associated Thromboembolism in Neonates: A Retrospective Case-Control Study

This study aimed to examine whether the transfusion of donor blood products, abnormal coagulation or inflammation increase the risk of venous thromboembolism (VTE) associated with central venous catheters (CVC) in neonates. A retrospective case-control study including 25 neonates with CVC-associated VTE and tightly matched controls with CVC, but without VTE was performed. The frequency of (i) abnormal coagulation screens, (ii) increased inflammatory marker proteins before catheter insertion, or (iii) catheter-associated blood stream infection did not differ between cases and controls. No difference was found in the number or type of transfusions within the last day before VTE. However, the total number of transfusions in the time period between catheter placement and VTE diagnosis (median 6.5 d) was significantly higher (P<0.001) in cases (44 red blood cell, 61 plasma, and 18 platelet transfusions) compared with an equal median time period of 7 days postcatheter insertion in controls (26/24/11). In conclusion, intensive transfusion treatment (through a peripheral line) after CVC insertion was associated with a higher risk of VTE (odds ratio 7.58; 95% confidence interval, 0.84-68.46), suggesting that transfusion of adult donor blood products into the cellular and plasmatic hemostatic system of the neonate increases the risk for CVC-associated VTE.

Is There Value in Venous Thromboembolism Chemoprophylaxis After Pediatric Scoliosis Surgery? A 28-Year Single Center Study

BACKGROUND

With a recognized increase in the incidence of venous thromboembolism (VTE) in children, especially in those with complex, chronic conditions, it is important for patient safety and risk management to identify subgroups that would benefit from prophylactic treatment. The aim of our study was to assess whether scoliosis surgery in children was associated with an increased incidence of VTE, including deep venous thrombosis (DVT) and pulmonary embolism, and if chemoprophylaxis is warranted.

METHODS

We reviewed our institution's Pediatric Orthopaedic Spine Database (1992-2019) to identify patients who had a symptomatic VTE postoperatively.

RESULTS

There were 1471 patients (1035 female, 436 male) with a mean age at surgery of 12.1±3.2 years (range, 1 to 18 y) underwent posterior spinal fusion and instrumentation (2131 procedures). No patients were given pharmacological VTE prophylaxis, and no routine screening for VTE was performed. Two patients had a lower extremity DVT (0.13%) within 6 months following surgery, (range, 55 to 161 d). Neither patient had a subsequent pulmonary embolism. They were 9 and 17 years of age with a diagnosis of neuromuscular scoliosis (1 each postpolio and myelodysplasia). One affected patient had a central venous line inserted perioperatively, a known risk factor for thromboembolism. All DVTs were treated with appropriately dosed anticoagulants. None had a family history of hypercoagulation.

CONCLUSIONS

The risk of symptomatic VTE is extraordinarily low after pediatric spinal deformity surgery. Mechanical prophylaxis is sufficient in most cases. Further multi-center studies may help identify patient specific risk factors.

Catheter related thrombosis in hospitalized infants: A neural network approach to predict risk factors

INTRODUCTION

We sought to investigate the predictors of catheter-related thrombosis (CRT) in a cohort of critically ill hospitalized infants and using a novel approach (the artificial neural network - ANN) in combination with conventional statistics to identify/confirm those predictors.

METHODS

We performed a retrospective analysis of all infants with a central or peripherally inserted central venous catheter (CVC/PICC) between 2015 and 2018. ANN was generated to investigate the predictors of CRT. The predictive variables examined in the ANN were age, gender, weight, co-morbid conditions, line type, use of ultrasound (USG), emergent line placement, location of line tip, any major surgical procedures, use of mechanical ventilation, exposure to cardio-pulmonary bypass (CPB), past-history of CVC/PICC, or thrombosis. Binary logistic regression was performed to calculate odds ratios (ORs) and determine which factors were significant in predicting CRT.

RESULTS

Of total of 613 infants, 59.9% of patients had a history of previous CVC or PICC and 12.2% had a history of thrombus as documented by USG in the past three months. CPB exposure was present in 48.1%. The incidence of CRT was 10.7%. Independent predictors of CRT were the line tip in IVC (OR: 2.37, 1.08-5.21, P = 0.032), history of thrombosis (OR: 2.40, 1.16-4.96, P = 0.019), previous CVC/PICC (OR: 2.80, 1.24-6.33, P = 0.014) and exposure to CPB (OR: 2.749, 1.08-6.98, P = 0.034). A sensitivity analysis was performed to determine the normalized importance of each variable used to create the ANN. The most important variables were age (with normalized importance of 100%), history of thrombosis, weight, and exposure to CPB (normalized importance of 68.2%).

CONCLUSIONS

Nearly 1 in 10 infants developed CRT. We found that catheter tip in IVC, exposure to CPB, history of vein thrombosis and history of CVC/PICC placement in the past 3 months are independently associated with a higher risk of CRT in infants by using conventional and neural network methods.

Central Vascular Thrombosis in Neonates with Congenital Heart Disease Awaiting Cardiac Intervention

Central vascular thrombosis (CVT) in critically ill neonates carries significant clinical implications. Neonates with congenital heart disease (CHD) awaiting cardiac intervention might be associated with increased risk of thrombosis. Outcome analysis was undertaken. An analysis of 77 neonates with CHD who were admitted to the NICU prior to cardiac intervention between January 2015 and December 2016 was undertaken. Patients requiring extracorporeal life support prior to any cardiac intervention, or receiving prophylactic anticoagulation not related to central vascular catheter (CVC) were excluded. Diagnosis of CVT was provided based on clinical indication and verified with imaging that warranted anticoagulation therapy. Location of CVC and extent of CVT along with treatments, outcomes, and vascular access types and durations were assessed. Logistic regression multivariate analysis was used to assess predictors of outcome. Neonates with CHD were complicated with CVT in 10.4%. Longer duration of CVC was also associated with thrombosis in neonates with CHD (72.7 days vs. 29.3 days, p < 0.001). Independent predictors of outcome included lower gestational age and CHD with single-ventricle (SV) anatomy (p < 0.05). In neonates with CHD awaiting cardiac intervention risk of CVT is substantial. Duration CVC, lower gestational age and SV anatomy are risk determinants of outcome. Standardized development of customized surveillance protocols tailored to this unique subsets of neonates and adherence to quality guidelines can influence outcome.

FondaKIDS III: A long-term retrospective cohort study of fondaparinux for treatment of venous thromboembolism in children

BACKGROUND

The incidence of venous thromboembolism (VTE) and use of anticoagulation are rising in children, but treatment options remain limited. As a newer anticoagulant, fondaparinux may be a safe and effective alternative with the benefit of once-daily dosing, but there is relatively little data supporting its use.

PROCEDURE

This retrospective cohort study describes the long-term dosing, efficacy, and safety of fondaparinux for treatment of VTE in children at a single institution. The study included children <18 years old treated with fondaparinux for VTE between 2008 and 2018. Descriptive statistics were used to present the findings.

RESULTS

A total of 277 patients were identified and analyzed in this study. Seventy-six percent of patients reached therapeutic levels with 0 or 1 dose adjustments over a median treatment duration of 93 days. Of the patients included in the efficacy analysis, 91% of patients had improvement in their clot status, including 69% (160/233) with complete resolution and 22% (53/233) with partial resolution. Twenty-six patients (11%) had VTE recurrence, but only seven (3%) of the new thrombi developed while on fondaparinux. Major bleeding occurred in seven patients (2.5%), primarily in patients with underlying medical conditions with increased bleeding risk. Minor bleeding occurred in 53 patients (19%).

CONCLUSIONS

This study demonstrates the stable long-term pediatric dosing of fondaparinux with similar efficacy and safety when compared to other anticoagulants. Given its advantages, fondaparinux can be considered a reasonable alternative for treatment of VTE in children.

Gamer's Thrombosis: A Review of Published Reports

Background: Thrombosis, well known as a condition of the elderly, is occurring in the otherwise healthy adolescent population. Immobility is a significant risk factor for venous thromboembolism (VTE), and adolescents who play video games are immobile for extended periods of time. Some are presenting with VTE. When other risk factors such as obesity are present, the risk of VTE formation increases. We provide a review of published case reports regarding gaming and thrombosis.

Methods: We searched PubMed, Scopus, Web of Science, and EBSCO for articles published through July 2019, using the keywords “computer game thrombosis,” “computer game pulmonary embolism,” “computer game deep vein thrombosis,” “video game thrombosis,” “video game pulmonary embolism,” and “video game deep vein thrombosis.”

Results: Of the 26 articles we identified, we included 12 articles in our review that report a total of 15 cases, of which 2 resulted in fatalities. Modifiable risk factors included cigarette use, being overweight, birth control use, and prolonged immobility. Anticoagulation was the principal treatment modality in patients presenting with gaming thrombosis.

Conclusion: We strongly encourage screening gamers for possible VTEs if clinically warranted.

Incidence of venous thromboembolism in hospitalized pediatric neurosurgical patients: a retrospective 25-year institutional experience

PURPOSE

Venous thromboembolism (VTE) refers to both deep venous thrombosis (DVT) and pulmonary embolism (PE). The risk of VTE in adult neurosurgical patients is thoroughly studied. However, the incidence and risk of VTE in a comprehensive pediatric neurosurgical population is not well-defined. The available pediatric data consists of reviews of specific high-risk groups, such as trauma, critical care, or cancer patients. This may not be reflective of the entire spectrum of a high-volume pediatric neurosurgery practice. This study was undertaken to analyze the incidence and risk factors of VTE in all hospitalizations evaluated by a pediatric neurosurgery service over a 25-year period.

METHODS

A retrospective review of electronic medical records was performed for 9149 hospitalizations in 6374 unique patients evaluated by the pediatric neurosurgery service at Riley Hospital for Children (Indianapolis, IN, USA) from 1990-2014. During this time period, there was no standardized VTE prevention protocol. The study group included all patients less than 18 years of age. Patients with a known pre-existing VTE or pregnancy were excluded.

RESULTS

VTE was diagnosed in 20 of the 9149 (0.22%) hospitalizations, in 18 unique patients. All DVTs were diagnosed via Doppler ultrasound and/or computed tomography. Anatomic clot locations included 9 in the upper extremity (0.098% of hospitalizations), 8 in the lower extremity (0.087%), and 4 (0.044%) pulmonary emboli. Ten of the 20 occurred in hospitalizations where the patient underwent surgery, although the need for surgery was not a statistically significant risk factor. Sixteen of the 20 (80%) occurred in patients with at least one form of central venous line (p < 0.00001). There was one VTE-related death (0.01%).

CONCLUSIONS

In all pediatric neurosurgical patients, a VTE was found in 0.22% of hospitalizations over a 25-year span. Statistically significant risk factors for VTE included central venous line placement, paralysis, malignancy, intubation greater than 48 h, and hypercoagulable state.

Role of direct oral anticoagulants in patients with kidney disease

The anticoagulation field is experiencing a renaissance that began with regulatory approval of the direct thrombin inhibitor dabigatran, a direct oral anticoagulant (DOAC), in 2010. The DOAC medication class has rapidly evolved to include the additional approval of 4 direct factor Xa inhibitors. Commensurately, DOAC use has increased and collectively account for the majority of new anticoagulant prescriptions. Despite exclusion of patients with moderate-to-severe kidney disease from most pivotal DOAC trials, DOACs are increasingly used in this setting. An advantage of DOACs is similar or improved antithrombotic efficacy with less bleeding risk when compared with traditional agents. Several post hoc analyses, retrospective studies, claims data studies, and meta-analyses suggest that these benefits extend to patients with kidney disease. However, the lack of randomized controlled trial data in specific kidney disease settings, with their unique pathophysiology, should be a call to action for the kidney community to systematically study these agents, especially because early data suggest that DOACs may pose less risk of anticoagulant-related nephropathy than do vitamin K antagonists. Most DOACs are renally cleared and are significantly protein bound in circulation; thus, the pharmacokinetics of these drugs are influenced by reduced renal function and proteinuria. DOACs are susceptible to altered metabolism by P-glycoprotein inhibitors and inducers, including drugs commonly used for the management of kidney disease comorbidities. We summarize the currently available literature on DOAC use in kidney disease and illustrate knowledge gaps that represent important opportunities for prospective investigation.

Association of perioperative red blood cell transfusion with postoperative venous thromboembolism in pediatric patients: A propensity score matched analysis

OBJECTIVE

To examine the association between perioperative red blood cell (RBC) transfusion and postoperative venous thromboembolism (VTE) in pediatric surgical patients.

METHODS

Retrospective cohort study using the National Surgical Quality Improvement Project Pediatric, a validated registry of 118 United States children's hospitals. Patients under 19 years of age undergoing a surgical procedure between 2012 and 2017 were included, with the main exposure being RBC transfusion in the perioperative period (48 hours prior to operation to 72 hours after operation). The primary 30-day outcome of interest was a postoperative VTE requiring therapy. Risk-adjusted odds ratios (aOR) were calculated using multiple logistic regression. Subgroup analyses were performed across multiple surgical specialties. Sensitivity analyses were performed after (a) imputation for missing variables and (b) propensity score matching.

RESULTS

During the study years, 482 867 pediatric patients (56.7% male; median age, 6 years [interquartile range, 1-12 years]) underwent an operation. Of these, 30 879 (6.4%) received at least one perioperative RBC transfusion. Postoperative VTE requiring therapy occurred in 618 patients (0.13%). After adjustment for multiple risk factors, perioperative RBC transfusion was associated with an increased risk of VTE (aOR 2.4; 95% CI, 1.9-3.0). The increased VTE risk persisted after imputation of missing demographic and clinical data as well as after 1:1 propensity score matching (29 811 matched pairs, aOR 2.2; 95% CI, 1.7-2.8).

CONCLUSIONS

Perioperative RBC transfusion is associated with an increased, albeit still very low, risk of postoperative VTE in pediatric patients. Patients receiving blood in the perioperative period may benefit from additional monitoring or VTE prophylaxis.

Venous thromboembolism in chronic pediatric heart disease is associated with substantial health care burden and expenditures

ABSTRACT

Background: Venous thromboembolism (VTE) is a complication in children with chronic pediatric heart disease (CPHD). The influence of acute VTE risk factors and the health care burden associated with VTE in CPHD is unknown.Methods: Children <18 years of age with a CPHD diagnostic code were identified from the 2003-2013 MarketScan Commercial Databases. VTE diagnoses were identified either concomitantly with initial CPHD diagnoses or during a 6-month follow-up. The associations between demographic and clinical characteristics and VTE among children with CPHD, stratified by recent cardiac surgery, were assessed by multivariable logistic regression models. Estimates of health care utilization were compared using Wilcoxon rank-sum tests.Results: VTE events occurred in 957 of 120 884 children with CPHD (0.8%). In-hospital mortality was significantly higher in children with VTE. Single-ventricle physiology had the highest VTE rate (2.3%). All comorbid conditions were significantly associated with VTE, but the prevalence was highest in children with recent cardiac (11.1%) or noncardiac surgery (7.8%). The magnitude of association between noncardiac comorbidities and acquired acute cardiovascular conditions and VTE were larger for children without a recent cardiac surgery. Children with VTE had significantly higher health care utilization.Conclusions: VTE in CPHD is associated with significantly increased health care resource utilization and in-hospital mortality. All of the comorbid conditions examined were significantly associated with VTE, but a recent surgical procedure, especially cardiac surgery, conferred the highest VTE risk. Although confounding inherently limits observational studies, these findings provide practical information about the health care costs among patients with CPHD and VTE.

In vitro assessment of edoxaban anticoagulant effect in pediatric plasma

INTRODUCTION

Anticoagulant therapy in pediatric patients remains an issue and safer therapies, such as direct oral anticoagulants could overcome the limitations of conventional anticoagulant treatments in this population. Edoxaban, a factor Xa inhibitor, is used for the prevention and treatment of venous thromboembolism. Due to its pharmacokinetic characteristics, edoxaban is a promising candidate molecule for children. This study compared edoxaban in vitro effect in children and adults.

MATERIALS AND METHODS

Blood samples were prospectively collected from 87 adults and 97 children (n = 12: <2 year-old; n = 8: 2-4 year-old; n = 9: 5-7 year-old; n = 14: 8-9 year-old; n = 10: 10-13 year-old; n = 15: 14-15 year-old; and n = 29: 16-18 year-old). Plasma samples were supplemented in vitro with edoxaban to a final concentration of 50, 150 or 300 ng/mL, and then edoxaban effect on prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen (Clauss assay), specific anti-factor Xa activity and thrombin generation assay (TGA) (with 5pM tissue factor and 4 nM phospholipids) was evaluated.

RESULTS

PT, aPTT, and specific anti-Xa activity exhibited similar dose-dependent responses to edoxaban in the different age groups. The reduction of thrombin peak, the most edoxaban-sensitive TGA parameter, was similar in adults and children, but for the youngest group (<2 year-old) where the peak value reduction (median [Q1-Q3]) was higher than in adults (51% [44-59] versus 40% [32-46], p < 0.01; 74% [63-80] versus 65% [58-70], p < 0.05; and 84% [73-88] versus 76% [70-80], p < 0.05 for 50, 150 and 300 ng/mL edoxaban, respectively).

CONCLUSIONS

Edoxaban in vitro effect are comparable in children and adults except in the <2-year-old group.

D-dimer in Adolescent Pulmonary Embolism

BACKGROUND

D-dimer is used to aid in diagnosing adult pulmonary embolism (PE). D-dimer has not been validated in adolescents. Clinicians must balance the risk of overtesting with that of a missed PE. D-dimer may be useful in this context. This study evaluates D-dimer in PE-positive and PE-negative adolescents.

METHODS

PE-positive patients < 22 years were diagnosed with PE by computed tomography (CT) or high-probability ventilation/perfusion, seen at emergency departments (EDs)/hospitals within a 16-hospital system across two states, January 1998 through December 2016. Of the 189 PE-positive patients, 88 (46.5%) had a D-dimer and were matched 1:1 by age, sex, and race to patients suspected of PE but confirmed negative by CT angiogram.

RESULTS

Ages of PE-positive patients ranged from 13 to 21 years, 64 (73%) were female, and 52 (60%) were Caucasian. Mean D-dimer was significantly higher (3,256 ng/mL, 95% confidence interval [CI] = 2,505-4,006 ng/mL) in PE-positive versus PE-negative patients (1,244 ng/mL, 95% CI = 493-1,995 ng/mL; p < 0.001). Mean D-dimer was higher in patients with massive or submassive PE (8,742 ng/mL, 95% CI = 5,994-11,491 ng/mL), followed by PE in central (4,795 ng/mL [95% CI = 3,465-6,125 ng/mL), lobar (3,758 ng/mL [95% CI = 1,841-5,676), and distal (2,327 ng/mL [95% CI = 1,273-3,381 ng/mL]) arteries. When comparing thresholds of positive D-dimer (≥500, ≥750, and ≥1,000 ng/mL), D-dimer had sensitivities of 90, 82, and 67% and specificities of 16, 53, and 67%, respectively. Negative predictive values were 61, 75, and 71% while positive likelihood ratios were 1.1, 1.8, and 2.2, respectively.

CONCLUSIONS

This study represents the largest available cohort of adolescent patients examining the diagnostic value of D-dimer for PE. Our results indicate that depending on the threshold selected, D-dimer can be a sensitive test for PE in adolescents and that discriminative value is higher for a cutoff of 750 ng/mL than that for 500 ng/mL. Prospective studies investigating the diagnostic value of D-dimer and a clinical decision rule for PE in pediatrics are needed.

Risk factors for venous thromboembolic events in pediatric surgical patients: Defining indications for prophylaxis

BACKGROUND

Venous thromboembolism (VTE) in pediatric surgical patients is a rare event. The risk factors for VTE in pediatric general surgery patients undergoing abdominopelvic procedures are unknown.

STUDY DESIGN

The American College of Surgeon's National Surgical Quality Improvement Program-Pediatric (NSQIP-P) database (2012-2015) was queried for patients with VTE after abdominopelvic general surgery procedures. Patient and operative variables were assessed to identify risk factors associated with VTE and develop a pediatric risk score.

RESULTS

From 2012-2015, 68 of 34,813 (0.20%) patients who underwent abdominopelvic general surgery procedures were diagnosed with VTE. On multivariate analysis, there was no increased risk of VTE based on concomitant malignancy, chemotherapy, inflammatory bowel disease, or laparoscopic surgical approach, while a higher rate of VTE was identified among female patients. The odds of experiencing VTE were increased on stepwise regression for patients older than 15 years and those with preexisting renal failure or a diagnosis of septic shock, patients with American Society of Anesthesia (ASA) classification ≥ 2, and for anesthesia time longer than 2 h. The combination of age > 15 years, ASA classification ≥ 2, anesthesia time > 2 h, renal failure, and septic shock was included in a model for predicting risk of VTE (AUC = 0.907, sensitivity 84.4%, specificity 88.2%).

CONCLUSION

VTE is rare in pediatric patients, but prediction modeling may help identify those patients at heightened risk. Additional studies are needed to validate the factors identified in this study in a risk assessment model as well as to assess the efficacy and cost-effectiveness of prophylaxis methods.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Risk Factors for Neonatal Venous and Arterial Thromboembolism in the Neonatal Intensive Care Unit-A Case Control Study

OBJECTIVE

To identify risk factors associated with venous and arterial thrombosis in sick neonates admitted to the neonatal intensive care unit.

STUDY DESIGN

A case-control study was conducted at 2 centers between January 2010 and March 2014 using the Children's Hospital Neonatal Database dataset. Cases were neonates diagnosed with either arterial or venous thrombosis during their neonatal intensive care unit stay; controls were matched in a 1:4 ratio by gestational age and presence or absence of central access devices. Bivariable and conditional logistic regression analyses for venous and arterial thrombosis were performed separately.

RESULTS

The overall incidence of neonatal thrombosis was 15.0 per 1000 admissions. A higher proportion of neonates with thrombosis had presence of central vascular access devices (75% vs 49%; P < .01) were of extremely preterm gestational age (22-27 weeks; 26% vs 15.0%; P <.05) and stayed ≥31 days in the neonatal intensive care unit (53% vs 32.9%; P <.01), when compared with neonates without thrombosis. A final group of 64 eligible patients with thrombosis and 4623 controls were analyzed. In a conditional multivariable logistic regression model, venous thrombosis was significantly associated with male sex (AOR, 2.12; 95% CI, 1.03-4.35; P = .04) and blood stream infection (AOR, 3.47; 95% CI, 1.30-9.24; P = .01).

CONCLUSIONS

The incidence of thrombosis was higher in our neonatal population than in previous reports. After matching for central vascular access device and gestational age, male sex and blood stream infection represent independent risk factors of neonatal venous thrombosis. A larger cohort gleaned from multicenter data should be used to confirm the study results and to develop thrombosis prevention strategies.

Inferior vena cava atresia predisposing to acute lower extremity deep vein thrombosis in children: A descriptive dual-center study

PURPOSE

Thrombosis in the healthy pediatric population is a rare occurrence. Little is known about the optimal treatment or outcomes of children with unprovoked acute lower extremity (LE) deep vein thrombosis (DVT) associated with atresia of the inferior vena cava (IVC).

METHODS

We retrospectively analyzed the records of patients with acute LE DVT subsequently found to have IVC atresia who presented to two tertiary pediatric institutions between 2008 and 2016. Data were reviewed for thrombophilia risk factors, treatment, and outcomes.

RESULTS

Eighteen patients, aged 13-18 years (median: 16 years), presenting with acute LE DVT were found to have IVC atresia. Three patients also presented with pulmonary embolism. Fourteen patients underwent site-directed thrombolysis in addition to anticoagulation. Five patients (28%) had confirmed or suspected recurrent thrombosis. Thirteen patients (72%) had no identified provocation for DVT. Ten patients (56%) had post-thrombotic syndrome, and 17 of 18 patients remain on indefinite anticoagulation.

CONCLUSION

This study suggests that IVC atresia is a risk factor for LE DVT and pulmonary embolism in otherwise healthy children and highlights the importance of dedicated imaging of the IVC in young patients with unprovoked LE DVT. Indefinite anticoagulation may be considered in pediatric patients presenting with unprovoked thrombosis secondary to an atretic IVC.

Increasing Incidence and Recurrence Rate of Venous Thromboembolism in Paediatric Oncology Patients in One Single Centre Over 25 Years

Venous thromboembolism (VTE) is a serious complication in paediatric oncology patients. To identify the incidence, risk factors and recurrence rate of VTE in paediatric oncology patients, an observational, retrospective cohort study of all consecutive children (≤18 years) with malignancies, treated at the Emma Children's Hospital Academic Medical Centre between January 1989 and December 2013, was done. A matched case-control study in children with lymphomas was performed, to identify thrombotic risk factors. Cumulative recurrence-free survival after first VTE was estimated by the Kaplan-Meier method. Of the 2,183 children included (male: female = 1.4:1.0; median age, 6.6 years) with cancer, 78 patients developed VTE (3.6%; 95% confidence interval [CI], 2.8-4.4). The incidence increased from 0.8% (4/478, 95% CI, 0.0-1.6) between 1989 and 1993 to 10.4% (44/423, 95% CI, 7.6-13.4) between 2009 and 2013. Independent risk factors for VTE were age ≥ 12 years, acute lymphoblastic leukaemia (ALL) and lymphoma. The case-control study in lymphoma patients showed a trend for increased VTE incidence in stage IV lymphoma. Twelve (15.4%) patients developed recurrent thrombosis, 7 patients while on therapeutic or prophylactic anticoagulation. The cumulative recurrence-free survival after first VTE was 88.5, 87.1 and 80.6% after 1, 5 and 10 years, respectively. In conclusion, we demonstrated an increasing incidence of VTE in children with malignancies, with age ≥ 12 years, ALL and lymphoma as independent risk factors. The elevated recurrence rate underlines the importance of full anticoagulant therapy and might warrant prophylactic anticoagulation after first VTE during cancer treatment.

Identification of a "VTE-rich" population in pediatrics - Critically ill children with central venous catheters

BACKGROUND

The incidence of venous thromboembolism (VTE) is rising among inpatients in US hospitals, especially among kids with central venous catheters (CVCs) in the pediatric intensive care unit (PICU).

OBJECTIVES

To identify a sub-group of "VTE-rich" population among PICU children, and to assess the effect of VTE on morbidity and mortality.

METHODS

Data was extracted from a multicenter Virtual PICU Database, or VPS, for children with a CVC and presence of a VTE. The primary outcome variable was all cause mortality and secondary outcome measure was prolonged mechanical ventilation. Primary diagnoses and Pediatric risk of mortality 2 (PIM 2) score were also recorded.

RESULTS

The database identified 158,299 PICU patients who had a CVC. A total of 1602 patients had VTE (103 per 10,000 PICU patients). Multivariate analysis showed increased risk of VTE in patients who were <1year old (OR 1.48; 1.30-1.68), mechanically ventilated (OR 2.48; 2.07-2.98), had either a diagnostic (OR 2.32; 1.94-2.78) or therapeutic cardiac catheterization (OR 2.06; 1.66-2.55), PICC (OR 3.91; 3.50-4.37), and percutaneous CVC (OR 3.99; 3.48-4.61). Primary diagnoses associated with VTE were endocrinologic, immunologic, and gastrointestinal disorders. PICU patients with CVC and VTE had increased odds of mortality (OR 1.71; 1.47-2.00) after adjusting for factors associated with mortality, and fewer Ventilator Free Days (VFD) than patients without VTE.

CONCLUSIONS

Critically ill children with CVC have a significant risk of developing VTE. Identification of the above "VTE-rich" population may aid in design of clinical trials aimed at prevention of VTE among hospitalized PICU children.

Quality Initiative to Introduce Pediatric Venous Thromboembolism Risk Assessment for Orthopedic and Surgery Patients

BACKGROUND AND OBJECTIVES

Pediatric hospital-acquired venous thromboembolism (VTE) is costly, has high morbidity, and is often preventable. The objective of this quality-improvement effort was to increase the percentage of general surgery and orthopedic patients ≥10 years of age screened for VTE risk from 0% to 80%.

METHODS

At a freestanding children's hospital, 2 teams worked to implement VTE risk screening for postoperative inpatients. The general surgery team used residents and nurse practitioners to perform screening whereas the orthopedic team initially used bedside nursing staff. Both groups employed multiple small tests of change. Shared key interventions included refinement of a screening tool, provider education, mitigation of failures, and embedding the risk assessment task into staff workflow. The primary outcome measure, the percentage of eligible patients with a completed VTE risk assessment, was plotted on run charts. Secondary outcome measures for screened patients included the level of risk, the use of appropriate prophylaxis, and VTE events.

RESULTS

Median weekly percentage of general surgery patients screened for VTE risk increased from 0% to 86% within 12 months, and median weekly percentage of orthopedic patients screened for VTE risk increased from 0% to 46% within 8 months. Among screened patients, the majority were at low or moderate risk for VTE and received prophylaxis in accordance with or beyond guideline recommendations. No screened patients developed VTE.

CONCLUSIONS

Quality-improvement methods were used to implement a VTE risk screening process for postoperative patients. Using providers as screeners, as opposed to bedside nurses, led to a greater percentage of patients screened.

Paediatric venous thromboembolism: a report from the Italian Registry of Thrombosis in Children (RITI)

BACKGROUND

The Italian Registry of Thrombosis in Children (RITI) was established by a multidisciplinary team with the aims of improving knowledge about neonatal and paediatric thrombotic events in Italy and providing a preliminary source of data for the future development of specific clinical trials and diagnostic-therapeutic protocols.

MATERIALS AND METHODS

We analysed the subset of RITI data concerning paediatric systemic venous thromboembolic events that occurred between January 2007 and June 2013.

RESULTS

Eighty-five deep venous thromboses and seven pulmonary emboli were registered in the RITI. A prevalence peak was observed in children aged 10 to 18 years and, unexpectedly, in children aged 1 to 5 years. A central venous line was the main risk factor (55% of venous thromboembolic events); surgery (not cardiac) (25%), concomitant infections (23%) and malignancy (22%) were the clinical conditions most often associated with the onset of venous thromboembolism. There was a diagnostic delay of more than 24 hours in 37% of the venous thromboembolic events. Doppler ultrasound was the most widely used test for the objective diagnosis of deep venous thrombosis (87%). Antithrombotic therapy was administered in 96% of venous thromboembolic events, mainly low molecular weight heparin (60%). In 2% of cases recurrences occurred, while post-thrombotic syndrome developed in 8.5% of cases.

DISCUSSION

Although the data from the RITI are largely in agreement with published data, peaks of prevalence of thrombosis, risk factors and objective tests used for the diagnosis showed some peculiarities which may deserve attention.

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.

Venous Thromboembolism in Children with Cancer and Blood Disorders

Venous thromboembolism (VTE) in children is multifactorial and most often related to a combination of inherited and acquired thrombophilias. Children with cancer and blood disorders are often at risk for VTE due to disease-related factors such as inflammation and abnormal blood flow and treatment-related factors such as central venous catheters and surgery. We will review risk factors for VTE in children with leukemia, lymphoma, and solid tumors. We will also review risk factors for VTE in children with blood disorders with specific focus on sickle cell anemia and hemophilia. We will present the available evidence and clinical guidelines for prevention and treatment of VTE in these populations.

Prothrombotic Risk Factors and Preventive Strategies in Adolescent Venous Thromboembolism

Venous thromboembolism (VTE) in adolescents is a serious condition that requires prompt recognition and optimal management to prevent mortality and long-term morbidity. Adolescents account for a large proportion of cases of VTE in children. As teenagers transition from childhood to adulthood, they are at risk of developing medical conditions and exposure to risky habits that predispose them to VTE. This review focuses on the variety of risk factors and comorbidities seen in adolescent VTE and takes a quick look into risk-based preventive strategies for primary and secondary prevention.

Association of Obesity and Pediatric Venous Thromboembolism

BACKGROUND

The incidence of venous thromboembolism (VTE) is increasing among pediatric patients in the United States. Previous studies on obesity as a risk factor have produced mixed results.

METHODS

We completed a retrospective chart review of patients aged 2 to 18 years with VTE identified by using International Classification of Diseases, Ninth Revision, codes and confirmed by imaging. Patients were admitted between January 2000 and September 2012. Control subjects were matched on age, gender, and the presence of a central venous catheter. Data were collected on weight, height, and risk factors, including bacteremia, ICU admission, immobilization, use of oral contraceptives, and malignancy. Underweight patients and those without documented height and weight data were excluded. Independent predictors of VTE risk were identified by using univariate and multivariate analyses.

RESULTS

We identified 88 patients plus 2 matched control subjects per case. The majority of cases were nonembolic events (77%) of the lower extremity (25%) or head and neck (22%) confirmed by ultrasound (43%) or computed tomography scan (41%). A statistically significant association was found between VTE and increased BMI z score (P = .002). In multivariate analysis, BMI z score (odds ratio [OR]: 3.1; P = .007), bacteremia (OR: 4.9; P = .02), ICU stay (OR: 2.5; P = .02), and use of oral contraceptives (OR: 17.4; P < .001) were significant predictors.

CONCLUSIONS

In this single-institution study, the diagnosis of VTE was significantly associated with overweight and obesity. Further study is needed to fully define this association.

Postoperative Complications in Pediatric Inflammatory Bowel Disease: A Population-based Study

BACKGROUND

We describe, in a population-based cohort, the incidence of and factors associated with postoperative complications (POCs) in pediatric-onset inflammatory bowel disease.

METHODS

Using the pediatric population-based EPIMAD Cohort (1988-2004), among 692 incident inflammatory bowel disease cases, 128 patients with Crohn's disease (CD) and 25 with ulcerative colitis (UC) (22%) had undergone at least 1 major abdominal surgery at a median age of 16 years [interquartile range, Q1-Q3 = 14-17]. Factors associated with POC were assessed using Cox models.

RESULTS

After a median postoperative follow-up of 8 years (3-12), 76 (49.7%) patients had experienced at least 1 POC with a total of 113 complications. The frequency of severe POC (grade >2) was similar in CD and UC (28% of all complications versus 27%, P = 0.95). A total of 64 early POCs (within 30 d of surgery) were observed in 47 patients (31%), with 33 being infectious and 31 noninfectious, higher in UC than in CD (25% of patients with CD versus 60% of patients with UC, P < 0.001). Forty-nine late POCs (≥30 d) were observed in 37 patients (24%). The occurrence of late POC was similar in UC and CD. The cumulative probability of POC was 31% (95% confidence interval, 24-39) at 1 month, 46% (38-54) at 1 year, and 48% (41-57) at 5 years. Multivariate analysis found that the UC type was the only factor associated with early POC (hazard ratio = 2.9; 95% confidence interval, 1.6-5.4).

CONCLUSIONS

One-half of the children with inflammatory bowel disease had experienced at least 1 POC. Only UC relative to CD was significantly associated with an increased risk of early POC.

Absence of venous thromboembolism risk following quadrivalent human papillomavirus vaccination, Vaccine Safety Datalink, 2008-2011

BACKGROUND

To investigate concerns about a potential association between quadrivalent human papillomavirus vaccination (HPV4) and venous thromboembolism (VTE), we conducted a self-controlled case series study in adolescents and young adults 9-26 years of age in the Vaccine Safety Datalink.

METHODS

We identified potential VTE cases diagnosed in 2008 through 2011 who had also received at least one HPV4 dose during that period. We confirmed each presumptive diagnosis by medical record review. We calculated incidence rate ratios (IRRs) and 95% confidence intervals (CI) to estimate the risk in the 1-60 day period following HPV4 exposure and in subsets of that period. IRRs were stratified by age, gender, hormonal contraceptive use, and recent surgery or trauma.

RESULTS

We identified 313 potential cases of VTE among HPV4 vaccinees, and 291 (93%) had sufficient medical records for review. Of these, we confirmed 156 (54%) cases. VTE was uncommon among males (n=3) and 9-12 year olds (n=4). Nearly all confirmed cases (97%) had at least one known risk factor for VTE, including hormonal contraceptive use, obesity, and hypercoagulability. Sixteen (10%) confirmed cases occurred in the 1-60 days following HPV4 exposure. The risk of VTE varied from 1.47 (95% CI: 0.47-4.64) in the 1-7 days following HPV4 exposure to 0.92 (95% CI: 0.54-1.57) in the 1-60 days following vaccination. It was not possible to calculate a stratified IRR for males due to small sample size; the other risk factors evaluated did not significantly affect the risk of VTE after HPV4 exposure.

CONCLUSION

The risk of developing VTE among 9- to 26-year-olds was not elevated following HPV4 exposure. Sample size limited our ability to rigorously evaluate potential effect modifiers, such as gender, through stratified analysis.

Evaluation of the risk of venous thromboembolism after quadrivalent human papillomavirus vaccination among US females

After the Food and Drug Administration (FDA) licensed quadrivalent human papillomavirus vaccine (HPV4) in 2006, reports suggesting a possible association with venous thromboembolism (VTE) emerged from the Vaccine Adverse Event Reporting System and the Vaccine Safety Datalink. Our objective was to determine whether HPV4 increased VTE risk. The subjects were 9-26-year-old female members of five data partners in the FDA's Mini-Sentinel pilot project receiving HPV4 during 2006-2013. The outcome was radiologically confirmed first-ever VTE among potential cases identified by diagnosis codes in administrative data during Days 1-77 after HPV4 vaccination. With a self-controlled risk interval design, we compared counts of first-ever VTE in risk intervals (Days 1-28 and Days 1-7 post-vaccination) and control intervals (Days 36-56 for Dose 1 and Days 36-63 for Doses 2 and 3). Combined hormonal contraceptive use was treated as a potential confounder. The main analyses were: (1) unadjusted for time-varying VTE risk from contraceptive use, (2) unadjusted but restricted to cases without such time-varying risk, and (3) adjusted by incorporating the modeled risk of VTE by week of contraceptive use in the analysis. Of 279 potential VTE cases identified following 1,423,399 HPV4 doses administered, 225 had obtainable charts, and 53 were confirmed first-ever VTE. All 30 with onsets in risk or control intervals had known risk factors for VTE. VTE risk was not elevated in the first 7 or 28 days following any dose of HPV in any analysis (e.g. relative risk estimate (95% CI) from both unrestricted analyses, for all-doses, 28-day risk interval: 0.7 (0.3-1.4)). Temporal scan statistics found no clustering of VTE onsets after any dose. Thus, we found no evidence of an increased risk of VTE associated with HPV4 among 9-26-year-old females. A particular strength of this evaluation was its control for both time-invariant and contraceptive-related time-varying potential confounding.

Risk of venous thromboembolism in children after general surgery

BACKGROUND/PURPOSE

The purpose of the study was to determine absolute and relative rates of venous thromboembolism (VTE) following general surgical procedures in children compared to the general population.

METHODS

We analyzed data from all patients under the age of 18years in the Clinical Practice Research Datalink, linked to Hospital Episode Statistics from England (2001-2011) undergoing a general surgical procedure and population controls. Crude rates of VTE and adjusted hazard ratios were calculated using Cox regression.

RESULTS

We identified 15,637 children who had a surgical procedure with 161,594 controls. Six children undergoing surgery had a VTE diagnosed in the year after compared to five children in the population cohort. The overall rate of VTE following surgery was 0.4 per 1000 person years (pyrs) (95% confidence interval [CI] 0.15-0.88) compared to 0.04 per 1000 pyrs (95% CI 0.02-0.09) in the population cohort. This represented a 9 fold increase in risk compared to the population cohort (adjusted hazard ratio [HR] 8.80; 95% CI 2.59-29.94).

CONCLUSIONS

Children are at increased risk for VTE following general surgical procedures compared to the general population however the absolute risk is small and given this the benefits of thromboprophylaxis need to be balanced against the risk of complications following its use.

Management of venous thrombosis in the pediatric patient

The incidence of venous thromboembolism in children has increased significantly over the past decade. The evaluation and management of the child with venous thromboembolism, while based on the adult experience, has its own particularities dictated by the differences in the hemostatic system of the newborn and child. The current review addresses the evaluation of pediatric patient with thrombosis as well as the established and emerging treatment interventions.

Healthcare burden of venous thromboembolism in childhood chronic renal diseases

BACKGROUND

Chronic renal diseases (CRD) are associated with approximately 5% of pediatric venous thromboembolism (VTE) cases, but the epidemiology of VTE in CRD is ill-defined.

METHODS

Children (<18 years) with CRD were identified from MarketScan® Research databases. The VTE status of subjects with CRD who qualified for this study was ascertained during the 6 months following the initial diagnosis of CRD. Demographics, healthcare utilization, mortality, and co-morbid conditions were assessed.

RESULTS

A total of 22,877 children with predefined CRD ICD-9-CM codes were identified between April 1, 2003 and June 30, 2012, among whom 0.55% had VTE. Our analysis revealed that in-hospital mortality was more likely in children with VTE than in those without VTE (11.9 vs. 0.9%, respectively; p < 0.0001). The usage of healthcare facilities, based on the number of inpatient admissions, length of stay, outpatient visits, and pharmaceutical claims, was also significantly higher in patients with VTE than in those without (p < 0.0001). Total mean healthcare expenditures for the 6-month follow-up period were 13-fold greater in the VTE group than in the group without VTE ($338,338 ± $544,045 vs. $25,171 ± $90,792; p < 0.0001). In a multivariate model, infection, hemodialysis, and trauma/surgery significantly increased the likelihood of VTE.

CONCLUSIONS

Venous thromboembolism is rare in children with CRD, but it is associated with higher mortality and healthcare utilization when present. Among the children with CRD enrolled in our study, the likelihood of VTE was increased among those with co-morbid, non-renal chronic conditions.