Venous thrombosis in children

Neonatal and Pediatric Pulmonary Vascular Disease

Pediatric patients are affected by a wide variety of pulmonary vascular diseases ranging from congenital anomalies diagnosed at birth to acquired diseases that present later in childhood and into adolescence. While some pulmonary vascular diseases present similarly to those seen in adults, other forms are unique to children. Knowledge of the characteristic imaging features of these diseases is essential to facilitate prompt diagnosis and guide clinical management.

Proportion and risk factors for hospital-acquired venous thromboembolism in children: a systematic review and meta-analysis of data from 20 million individuals in 22 countries

Background

Hospital-acquired venous thromboembolism (HA-VTE) in children has been widely regarded.

Objectives

We aimed to analyze the proportion and risk factors for HA-VTE in hospitalized children.

Methods

We conducted a comprehensive systematic search across 4 databases from 1990 to 2023. Cochran Q test was used to evaluate the heterogeneity of the effect sizes of study, and I2 statistic was used to quantify the heterogeneity. Pooled estimates were calculated by the inverse-variance weighted method in a fixed-effect model or a random-effect model when heterogeneity was low (I2 < 25%) or high (I2 > 25%), respectively.

Results

In total, 105 original papers and 20,718,294 patients were included in the study, and the proportion of HA-VTE in children was 4.1% (95% CI, 2.9%-5.2%). Although the proportion of venous thromboembolism increased over the various research periods, the differences were not statistically significant. In the subgroup analysis based on country, the proportion of pediatric HA-VTE was lowest in the United Kingdom and highest in Spain, whereas when based on region, the proportion was lowest in Asia and highest in North America. Multiple HA-VTE risk factors were identified, including central venous catheter use, age of >10 years, surgery, injury, infection, obesity, mechanical ventilation, blood transfusion, malignancy, coagulation and hemorrhagic disorders, and length of hospital stay.

Conclusion

In this study, we systematically analyzed the proportion and risk factors of HA-VTE in hospitalized children. Our findings provide valuable insights for the prevention and treatment of HA-VTE in pediatric patients.

Efficacy and safety of antithrombotic therapy for preventing and treating pediatric thromboembolic disease: a systematic review

This review used traditional and network meta-analyses (NMA) to conduct a comprehensive study of antithrombotic therapies in children with thromboembolic disease. We searched the PubMed, Embase, Cochrane Library, Web of Science and ClinicalTrials.gov databases from their inception to 26 February, 2023. And we finally included 16 randomized controlled trials. In the prevention of thromboembolic events (TEs), the use of anticoagulants had a low risk of TEs (relative risk (RR) 0.73, 95% CI 0.56 to 0.94) and a high risk of minor bleeding (RR 1.43, 95% CI 1.09 to 1.86) compared with no anticoagulants. In the treatment of TEs, direct oral anticoagulants (DOACs) were not inferior to standard anticoagulation in terms of efficacy and safety outcomes. In NMA, rivaroxaban and apixaban showed the lowest risk for TEs and major or clinically relevant nonmajor bleeding. According to the overall assessment of efficacy and safety, dabigatran may be the best choice for children with thromboembolic disease. The results of our study will provide references and suggestions for clinical drug selection.

Implementing a Pediatric Pulmonary Embolism Response Team Model: An Institutional Experience

Pulmonary embolism is increasing in prevalence among pediatric patients; although still rare, it can create a significant risk for morbidity and death within the pediatric patient population. Pulmonary embolism presents in various ways depending on the patient, the size of the embolism, and the comorbidities. Treatment decisions are often driven by the severity of the presentation and hemodynamic effects; severe presentations require more invasive and aggressive treatment. We describe the development and implementation of a pediatric pulmonary embolism response team designed to facilitate rapid, multidisciplinary, data-driven treatment decisions and management.

Thrombosis incidence in major paediatric burns

BACKGROUND

Major burns are associated with multiple risk factors for thrombosis such as decreased mobilization and systemic inflammation. It is unclear if these factors are offset by the inherent lower thrombosis risk in the paediatric patient. As such there is no consensus on thromboprophylaxis for paediatric burns patients, in contrast to this being a mainstay of treatment in the adult population. This retrospective cohort study examines the incidence of, and risk factors for, thrombotic events in major paediatric burns with a view to establish guidelines for prevention.

METHOD

Review of major paediatric burns, defined as % total body surface area (%TBSA) ≥30%, at the Adelaide Women's and Children's Hospital (WCH) over a 16-year period. Coding data and the local burns database were used to identify participants with subsequent review of case files.

RESULTS

Of the cohort (n = 23), six cases (26%) were complicated by thrombotic events. These patients had the most extensive burns averaging 68.5% TBSA, longer PICU admissions and associated interventions. These data points were more than doubled in the cohort diagnosed with a thrombus. Of the six events, five were secondary to central venous catheters (CVC) and one deep venous thrombosis (DVT) to the left calf.

CONCLUSION

The incidence of thrombotic events in our study was significant albeit in a small population. There is a strong association between large %TBSA and thrombus, with clots mostly forming around CVCs. While further research is required, this study demonstrates screening and targeted thromboprophylaxis may be required for major paediatric burns.

Epidemiology and risk factors for thrombosis in children and newborns: systematic evaluation and meta-analysis

BACKGROUND

Thrombosis is a serious condition in children and neonates. However, the risk factors for thrombosis have not been conclusively determined. This study aimed to identify the risk factors for thrombosis in children and neonates in Intensive Care Unit (ICU) through a meta-analysis to better guide clinical treatment.

METHODS

A systematic search of electronic databases (PubMed, Embase, Cochrane Library, WOS, CNKI, Wanfang, VIP) was conducted to retrieve studies from creation on 23 May 2022. Data on the year of publication, study design, country of origin, number of patients/controls, ethnicity, and type of thrombus were extracted. The publication bias and heterogeneity between studies were assessed, and pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using fixed or random effects models.

RESULTS

A total of 18 studies met the inclusion criteria. The incidence of thrombosis in children was 2% per year (95% CI 1%-2%, P < 0.01). Infection and sepsis (OR = 1.95, P < 0.01), CVC (OR = 3.66, [95%CL 1.78-7.51], P < 0.01), mechanical ventilation (OR = 2.1, [95%CL1.47-3.01], P < 0.01), surgery (OR = 2.25, [95%CL1.2-4.22], P < 0.01), respiratory distress (OR = 1.39, [95%CL0.42-4.63], P < 0.01), ethnicities (OR = 0.88, [95%CL 0.79-0.98], P = 0.78), gestational age (OR = 1.5, [95%CL1.34-1.68], P = 0.65)were identified as risk factors for thrombosis.

CONCLUSIONS

This meta-analysis suggests that CVC, Surgery, mechanical ventilation, Infection/sepsis, gestational age, Respiratory distress, and different ethnicities are risk factors for thrombosis in children and neonates in ICU. These findings may help clinicians to identify high-risk patients and develop appropriate prevention strategies.

TRIAL REGISTRATION

PROSPERO (CRD 42022333449).

Using an electronic medical record patient portal for warfarin self-management: Empowering children and parents

Background

Many children taking warfarin perform their international normalized ratio (INR) at home, with results phoned to a clinician who instructs warfarin dosing. Data suggest that parents can be supported to make warfarin dosing decisions themselves, a process known as patient self-management (PSM).

Objectives

This study aimed to determine the suitability and acceptability of warfarin PSM in children using the Epic Patient Portal.

Methods

Children currently performing INR patient self-testing were eligible. Participation involved an individualized education session, adherence to the PSM program, and participation in phone interviews. Clinical outcomes (INR time in therapeutic range and safety outcomes), patient portal functionality, and family experience were assessed. The hospital human research ethics committee approved the study and consent was obtained from parents/guardians.

Results

Twenty-four families undertook PSM. The median age of children was 11 years and all children had congenital heart disease. A median of 13 INRs was uploaded to the portal per family (range, 8-47) across a 10-month period. Before PSM, the mean time the INR was in therapeutic range was 71%; this increased to 79.9% during PSM (difference: P < .001). No adverse events were encountered. Eight families participated in a phone interview. The major theme identified was empowerment; minor themes that emerged included "gaining knowledge," "trust and responsibility builds confidence," "saving time," and "resources as a safety net."

Conclusion

This study demonstrates that communication via the Epic Patient Portal is satisfactory to families and offers a suitable option for PSM for children. Importantly, PSM empowers and builds confidence in families to facilitate management of their child's health.

Diagnosis of Internal Jugular Vein Septic Thrombophlebitis by Point-of-Care Ultrasound

ABSTRACT

Septic thrombophlebitis represents a rare but serious collection of diseases, which carry a high risk of morbidity and mortality requiring prompt and aggressive treatment. Diagnosis centers on identification of thrombus along with clinical and microbiologic data. We present a case where point-of-care ultrasound was used to diagnose septic thrombophlebitis of the internal jugular vein and expedite appropriate therapy. We further review the technique and literature for ultrasound diagnosis of venous thrombosis and associated thrombophlebitis.

Venous Thromboembolic Complications in Pediatric Gastrointestinal Diseases: Inflammatory Bowel Disease and Intestinal Failure

In children with gastrointestinal disorders such as inflammatory bowel disease (IBD) and intestinal failure (IF), the risk of venous thromboembolism (VTE) is increased. VTE may lead to pulmonary embolism, sepsis and central line infection, stroke and post-thrombotic syndrome. The purpose of this review is to summarize current knowledge and recent advances around VTE management in pediatric gastroenterology with a focus on IBD and IF. The VTE incidence in children with IBD is reported to be around 4-30 per 10,000 patient-years, with higher incidences for hospitalized children. While in general, IF is less common than IBD, the VTE incidence in children with IF is around 750 per 10,000 patient-years. The most common risk factors for development of VTE involve deviations leading to Virchow's triad (endothelial damage, stasis, and hypercoagulability) and include active inflammation, particularly with colonic involvement, presence of a central venous catheter, underlying thrombophilia, reduced mobility, surgery, and hospitalization. Classes of anticoagulants used for treatment of VTE are low molecular weight heparins and vitamin K antagonists. However, the use of direct oral anticoagulants for treatment or prevention of VTE has not been studied in this pediatric population yet. Pediatric gastroenterologists apply different VTE prevention and treatment strategies due to lack of literature and lack of consensus. We discuss the role of primary and secondary prophylactic use of anticoagulants, and provide tools and recommendations for screening, prevention and management for the specific pediatric populations.

Systemic Catheter-Related Venous Thromboembolism in Children: Data From the Italian Registry of Pediatric Thrombosis

BACKGROUND

Central venous catheters (CVCs) represent one of the main risk factors for venous thrombotic events (VTEs) in children.

METHODS

We studied the Italian Registry of Pediatric Thrombosis (RITI) with regard to systemic radiologically confirmed CVC-related VTEs (CVC-VTEs) occurred during 6.5 years in children aged 29 days to 18 years.

RESULTS

A total of 78 CVC-VTEs were included, which occurred in 76 patients (40/76, 53% males). CVC-VTEs comprised 67 non-cardiac VTEs (86%) and 11 intracardiac thrombotic events (ICTEs) (14%); the median age at onset was 19 and 17 months, respectively. The most frequent reason for CVC insertion was supportive therapy. The catheters were placed percutaneously in 85% of cases (56/66) and surgically in the remaining 15% (10/66). Peripherally inserted central catheters (PICCs) were used in 47% (31/66) cases, partially implanted catheters in 42% (28/66), non-implantable catheters in 7% (5/66), and totally implanted catheters (Port) in 2% (1/66). CVC-VTEs were symptomatic in 77% of cases (60/78), while in the remaining 23%, they were incidentally detected on the imaging performed for the underlying condition. The median time between CVC insertion and the onset of symptoms was 10 days in non-cardiac VTEs and 39 days in ICTEs. Doppler ultrasound was the diagnostic technique most frequently used. The venous compartment most frequently affected was the veins of the lower extremities (52%, 43/73). Anti-thrombotic treatment was administered in 96% of CVC-VTEs (75/78). About 2.6% (2/76) of patients experienced a second thrombotic event. At discharge, post-thrombotic syndrome was reported in 13.5% (5/37) events with available data, CVC replacement in 10.8% (4/47), and ischemic necrosis with toe finger amputation in 2.7% (1/37). Three patients died due to an underlying condition; no CVC-VTE-related deaths were reported.

CONCLUSIONS

We have carried out a registry-based study on CVC-VTEs in the children in Italy, providing the data that may help improve the detection and management of this CVC-related complication.

Antithrombin III Supplementation in a Premature Infant: Is There a Target Antithrombin Level?

The optimal antithrombin (AT) activity for low-molecular-weight heparin efficacy and the benefits of antithrombin III (ATIII) supplementation in premature infants diagnosed with venous thromboembolism are unknown. Currently, there are no neonatal-specific guidelines directing the appropriate target AT activity during supplementation. This case report describes a critically ill premature infant with a progressive, occlusive inferior vena cava thrombus who received supplemental ATIII during enoxaparin treatment. The patient did not achieve therapeutic anti-Xa levels despite increasing enoxaparin dosing to 3 mg/kg every 12 hours. ATIII supplementation sufficient to attain an AT activity of >40%, in combination with an enoxaparin dosing of >2 mg/kg every 12 hours, was needed to achieve therapeutic anti-Xa levels. Future large studies are needed to determine if there is an optimal target AT activity for critically ill premature infants.

Diagnosis and Management of Pediatric Venous Thromboembolism: New Therapies on the Horizon

ABSTRACT

The incidence of venous thromboembolism (VTE) is increasing in pediatric patients. Prompt recognition and evaluation of VTE in young patients could prevent significant morbidity or mortality. In contrast to VTE in adults, current treatment guidelines are largely based on expert opinion as limited randomized controlled trial data exist about the appropriate management in pediatric patients with traditional anticoagulants. However, recently approved direct-acting oral anticoagulants in adults are also being investigated in pediatric VTE and these data could inform future evidence-based treatment principles. Thus, healthcare providers must be well informed about the management of pediatric VTE and the data from these trials to date. This continuing medical education article will provide a summary of management of pediatric VTE with particular emphasis on emerging direct-acting oral anticoagulants.

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.

Thrombolytic therapy in preterm infants: Fifteen-year experience

OBJECTIVE

To report a single-center experience with thrombolytic therapy using recombinant tissue plasminogen activator (rt-PA) in preterm neonates with severe thrombotic events, in terms of thrombus resolution and bleeding complications.

STUDY DESIGN

This retrospective study included 21 preterm neonates with severe venous thrombotic events admitted to the neonatal intensive care unit, identified in our pharmacy database from January 2001 to December 2016, and treated with rt-PA until complete or partial clot lysis, no-response or bleeding complications. Our primary outcome was thrombus resolution.

RESULTS

Twenty-one preterm neonates were treated with rt-PA for an average of 2.9 cycles. Seventeen patients (80.9%) had superior vena cava thrombosis and superior vena cava syndrome. All patients had a central venous catheter, parenteral nutrition, mechanical ventilation, and sepsis. Fifteen patients (71.4%) were extremely preterm, 11 (52.4%) were extremely low birth weight, and seven (33.3%) were very low birth weight. The patency rate was 85.7%, complete lysis occurred in 11 (52.4%) patients, and partial lysis in seven (33.3%). Minor bleeding occurred in five (23.8%) patients, three patients (14.2%) had clinically relevant nonmajor bleeding events, and major bleeding occurred in six (28%) patients.

CONCLUSION

In this study, the rate of thrombus resolution in preterm neonates treated with rt-PA were similar to the percentages reported in children and adolescents, with a high rate of bleeding. Therefore, rt-PA thrombolytic therapy should only be considered as a treatment option for severe life-threatening thrombosis in premature neonates for whom the benefits of the thrombolytic treatment outweigh the risks of bleeding.

Venous Thrombosis in Children with Acute Lymphoblastic Leukemia Treated on DCOG ALL-9 and ALL-10 Protocols: The Effect of Fresh Frozen Plasma

Background  Venous thromboembolism (VTE) is an important complication for treatment of acute lymphoblastic leukemia (ALL) in children. Especially, ALL treatment, with therapeutics such as asparaginase and steroids, increases the thrombotic risk by reduction in procoagulant and anticoagulant proteins. Replacement of deficient natural anticoagulants by administration of fresh frozen plasma (FFP) may have a preventive effect on the occurrence of VTE.

Methods  We retrospectively analyzed all consecutive children (≤18 years) with ALL, treated on the Dutch Childhood Oncology Group (DCOG) ALL-9 and ALL-10 protocols at the Emma Children's Hospital Academic Medical Center between February 1997 and January 2012, to study the effect of FFP on VTE incidence, antithrombin and fibrinogen plasma levels, and VTE risk factors.

Results  In total, 18/205 patients developed VTE (8.8%; 95% confidence interval [CI]: 4.9–12.7%). In all patients, VTE occurred after asparaginase administration. In total, 82/205 patients (40%) received FFP. FFP supplementation did not prevent VTE or alter plasma levels of antithrombin or fibrinogen. In the multivariate analysis, VTE occurred significantly more frequently in children ≥12 years (odds ratio [OR]: 3.89; 95% CI: 1.29–11.73) and treated according to the ALL-10 protocol (OR: 3.71; 95% CI: 1.13–12.17).

Conclusion  FFP supplementation does not seem to be beneficial in the prevention of VTE in pediatric ALL patients. In addition, age ≥12 years and treatment according to the DCOG ALL-10 protocol with intensive and prolonged administration of asparaginase in combination with prednisone are risk factors. There is a need for effective preventive strategies in ALL patients at high risk for VTE.

Deep venous thrombosis of lower limbs in adolescents: a study in a tertiary hospital

BACKGROUND

Venous thromboembolism (VTE) - which includes deep venous thrombosis (DVT) and pulmonary embolism (PE) - has been increasingly recognized in the pediatric population. The estimated incidence is 0.07-0.14 cases per 10,000 children. Most cases are associated with two or more risk factors. Medium and long-term complications include recurrence and post-thrombotic syndrome (PTS).

OBJECTIVE

To characterize the adolescent population with the diagnosis of DVT of lower limbs in a tertiary hospital, regarding its clinical presentation, associated risk factors, treatment and outcome.

METHODS

Retrospective analysis of adolescents with the diagnosis of DVT of lower limbs in our hospital for a period of 7 years.

RESULTS

Eight patients were identified; seven were females; median age was 15 years. The main symptoms were local pain and edema. Left lower limb was affected in six patients. PE occurred in two cases. Positive family history of venous thromboembolism was found in five patients. Seven patients had at least two identifiable risk factors. Combined oral contraceptive pill use was the most common (seven patients). Factor V Leiden mutation was found in three patients and protein C deficiency in one. Iliac vein compression syndrome was diagnosed in one patient. The median time for discharge was 8 days. Election treatment was enoxaparin followed by warfarin, for a median period of 10.9 months. Three patients developed PTS.

CONCLUSIONS

Although uncommon, VTE is an emerging reality in adolescents, particularly in females using oral contraceptive pills. Appropriated prevention strategies and treatment are required as most orientations are extrapolated from adults.

Prevention of perioperative venous thromboembolism in pediatric patients: Guidelines from the Association of Paediatric Anaesthetists of Great Britain and Ireland (APAGBI)

The Association of Paediatric Anaesthetists of Great Britain and Ireland (APAGBI) Guidelines Working Group on Thromboprophylaxis in Children has reviewed the literature and where possible provided advice on the care of children in the perioperative period. Areas reviewed include the incidence of perioperative venous thromboembolism (VTE), risk factors, evidence for mechanical and chemical prophylaxis, and complications. Safe practice of regional anesthesia with anticoagulant prophylaxis is detailed. In summary, there are few areas of strong evidence. Routine prophylaxis cannot be recommended for young children. Postpubertal adolescents (approximately 13 years and over) are at a slightly increased risk of VTE and should be assessed for prophylaxis and may warrant intervention if other risk factors are present. However, the incidence of VTE is significantly lower than in the adult population. This special interest review presents a summary and discussion of the key recommendations, a decision-making algorithm and a risk assessment chart. For the full guideline, go to www.apagbi.org.uk/publications/apa-guidelines.

Pediatric Deep Venous Thrombosis Associated With Staphylococcal Infections: Single Institutional Experience

Deep venous thrombosis (DVT) has been previously reported in children with methicillin-resistant Staphylococcus aureus (MRSA). This study reviews our institutional experience by evaluating characteristics and outcomes of children with DVT and staphylococcal infections. Retrospective clinical data from 16 pediatric patients with DVT and staphylococcal infections over a 5-year period was obtained via medical record abstraction. Sixteen patients with a median age at diagnosis of 8 years were included. The most common infection encountered was osteomyelitis (56%). The most common isolated organism was MRSA (63%). Central venous catheters were present in 50% of cases. All patients received anticoagulation with low molecular weight heparin except 1 patient with superficial venous thrombosis who was managed conservatively. Fifty percent of patients had complete resolution of DVT by the end of treatment, 25% of the patients had early disappearance of the thrombus at 7 to 10 days. Only 2 patients (12.5%) had persistent thrombus at 6 months. Staphylococcal infections may increase the risk of DVT in children. Therefore, a high index of suspicion for DVT is warranted in children with Staphylococcal infections (particularly MRSA) to promptly diagnose, treat and minimize complications. Prophylactic anticoagulation in presence of staphylococcal infection, particularly MRSA, may be considered in future studies.

Evaluation of the age-dependent dosing recommendations for the administration of daily tinzaparin in children with thrombosis

Essentials The once-daily dosing of tinzaparin provides an advantage over other low molecular weight heparins. The recommended age-dependent doses of tinzaparin in children have not previously been validated. Once-daily administration of tinzaparin is a safe and effective treatment of childhood thrombosis. Recommended doses are appropriate but monitoring may be required due to inter-individual variation.

SUMMARY

Background The recommended starting doses of tinzaparin for the treatment of thrombosis in children have not previously been validated. There are few data to support the efficacy and safety of once-daily tinzaparin dosing in children with thrombosis. Objectives To investigate the use of tinzaparin for the treatment of childhood thrombosis, and to evaluate the age-dependent dosing recommendations and define outcomes in terms of efficacy and safety. Methods This was a retrospective cohort study of children aged 0 to < 16 years treated for thrombosis at a large teaching hospital in the UK between 2008 and 2015. Medical records were reviewed to evaluate tinzaparin dosing, anti-activated factor X (FXa) levels, and patient outcomes. Results Seventy-nine children were identified as having received tinzaparin. Dosing information was available for 57. Younger children required higher doses to reach a therapeutic level. The therapeutic dose requirement varied within age groups, supporting the use of anti-FXa monitoring. Over a median follow-up of 35 months, there were 13 (16%) bleeding episodes (two major; seven clinically relevant but non-major; and four minor). There were two (3%) recurrent episodes of thrombosis. Children were treated for a median duration of 3 months, and the majority (86%) remained on tinzaparin for the duration of their anticoagulant therapy. Conclusion Once-daily tinzaparin is a safe and effective treatment for childhood thrombosis, with rates of recurrence and bleeding similar to those for other anticoagulants used in children. The recommended starting doses are appropriate, but anti-FXa monitoring may be required, owing to interindividual variability in the therapeutic dose requirement.

USE OF WARFARIN IN PEDIATRICS: CLINICAL AND PHARMACOLOGICAL CHARACTERISTICS

Objective:

To describe how children respond to oral anticoagulation with warfarin, verifying the influence of age, clinical condition, route of administration of warfarin and use of total parenteral nutrition (TPN), as well as to describe risk factors for the occurrence of thrombotic events (TE) in childhood.

Methods:

A retrospective descriptive study including all patients ≤18 years old for whom warfarin was prescribed in a university hospital. Patients were divided according to clinical condition, age, route of medication administration and use of TPN. Data was collected from the patients’ medical records and the analysis considered the risk factors for TE already described in the literature, the time and the dose required in order to reach the first International Normalized Ratio (INR) in the target and the adverse events in this period. After reaching the INR, the maintenance of anticoagulation was verified by the prescribed dose and INR tests.

Results:

Twenty-nine patients were included in the study. The major risk factor for TE was the use of a central venous catheter in 89.6% of the patients. Patients with short bowel syndrome and total parenteral nutrition required significantly higher doses (p≤0.05) to achieve and maintain the INR in the target. Patients ≤1 year old needed longer periods and required an increased dose of anticoagulation and maintenance than older patients. The mean number of INR examinations below the target was 48.2% in the groups studied.

Conclusions:

The observed complexity of anticoagulant therapy reinforces the need to develop protocols that guide clinical practice.

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.

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.

A conceptual and practical approach to haemostasis in paediatric liver disease

Children with liver disease can develop severe bleeding episodes and thrombosis. Liver failure usually results in decreased levels of procoagulant and anticoagulant factors. Additional risk factors, including changes in vascular flow and endothelial function, are of importance for the development of bleeding or thrombosis in individual vascular beds. Detailed studies of haemostatic disturbances in the setting of paediatric liver disease are sparse and extrapolation from adult studies is common. The spectrum of liver diseases and the haemostatic system differs between children and adults. Specific paediatric liver diseases are reported to have more distinctive effects on haemostasis and the risk of bleeding and/or thrombosis.

CONCLUSION

we propose a model regarding haemostasis in paediatric liver disease, taking into account a number of specific variables and mechanisms, as well as the type of liver disease, which will provide a framework for clinical decision-making in these complex patients.

Quality improvement program reduces venous thromboembolism in infants and children with long-gap esophageal atresia (LGEA)

PURPOSE

Patients with long-gap esophageal atresia (LGEA) treated with the Foker process are at increased risk of venous thromboembolism (VTE). An institutional quality improvement program to decrease VTE risk factor exposure and utilize prophylactic anticoagulation was implemented. We aim to evaluate the efficacy and safety of a VTE risk-reduction program in patients with LGEA.

METHODS

Implementation and evaluation of a VTE risk-reduction program in patients with LGEA from 2012 to 2015 was performed. Symptomatic VTE with radiographic confirmation were defined as events. Post-program characteristics were evaluated and compared to a historical cohort.

RESULTS

Sixty-seven patients were identified. Two developed VTE (7 %) post-program implementation; compared to 13/40 (33 %) VTE incidence in the historical cohort (p = 0.018). Baseline demographics were similar, including age, esophageal atresia type and gap length. Post-protocol patients had fewer paralysis episodes (p = 0.004), paralysis days (p = 0.003), central venous catheters (p = 0.003), thoracotomies (p < 0.001), ventilator hours (p = 0.02), and decreased hospital (p < 0.001) and ICU stay (p < 0.001). All patients in the VTE risk-reduction program were exposed to prophylactic anticoagulation. No bleeding complications and/or thrombosis-related mortality occurred.

CONCLUSION

VTE risk-reduction program implementation decreased symptomatic VTE incidence with associated decreases in ICU and hospital length of stay. Prophylactic anticoagulation can be utilized safely in a complicated pediatric surgical population.

Advances in Multidetector CT Diagnosis of Pediatric Pulmonary Thromboembolism

Although pediatric pulmonary thromboembolism is historically believed to be rare with relatively little information available in the medical literature regarding its imaging evaluation, it is more common than previously thought. Thus, it is imperative for radiologists to be aware of the most recent advances in its imaging information, particularly multidetector computed tomography (MDCT), the imaging modality of choice in the pediatric population. The overarching goal of this article is to review the most recent updates on MDCT diagnosis of pediatric pulmonary thromboembolism.

Incidence of Deep Vein Thrombosis and Pulmonary Embolism in the Elective Pediatric Orthopaedic Patient

BACKGROUND

Although venous thromboembolism (VTE) has been well studied in the pediatric trauma population, rates of VTE associated with elective pediatric orthopaedic procedures have not been addressed in current literature. The purpose of this retrospective study was to identify the incidence of VTE in the elective pediatric orthopaedic surgical population and delineate subsets of this population at greatest risk. This study may provide valuable data to begin the process of resolving the controversy surrounding deep vein thrombosis prophylaxis in the pediatric orthopaedic population.

METHODS

The Pediatric Health Information System was queried for patients admitted on an ambulatory or inpatient basis, aged below 18 years, from January 2006 to March 2011 during which an elective orthopaedic surgery was the principal procedure performed. Patients with diagnoses or procedures related to infection, trauma, malignancy, or coagulopathies were excluded. Patients admitted through the emergency department or whose orthopaedic procedure was not performed on the admission date were excluded. Age, sex, ethnicity, race, admission year, and all procedures/diagnoses were recorded. The presence of VTE at the index admission or any subsequent readmission within 90 days was recorded. All criteria were coded using ICD-9-CM codes. Generalized logistic regression analyses were used to identify factors related to VTE.

RESULTS

A total of 143,808 admissions (117,676 patients) matched the inclusion criteria. Thirty-three had a VTE during the index admission with an additional 41 at subsequent readmissions, for a total incidence of 0.0515% by admission and 0.0629% by patient. In the multivariable model, variables significantly (P<0.05) related to VTE included increasing age, admission type, diagnosis of metabolic conditions, obesity, and/or syndromes, and complications of implanted devices and/or surgical procedures. No procedure variables were significantly related to VTE in the multivariable model.

CONCLUSIONS

The incidence of VTE in this cohort of pediatric patients undergoing elective orthopaedic surgery was 0.0515%. In children, underlying diagnosis seems to be a stronger predictor of VTE than procedures performed. Diagnosis with a metabolic condition, syndrome, and/or obesity, complications of implanted devices and/or surgical procedures, older age, and admission as an inpatient were significantly related to the development of a VTE.

LEVEL OF EVIDENCE

Level IV—case series.

Thrombosis in the Neonatal Intensive Care Unit

Neonates have the highest risk for pathologic thrombosis among pediatric patients. A combination of genetic and acquired risk factors significantly contributes to this risk, with the most important risk factor being the use of central venous catheters. Proper imaging is critical for confirming the diagnosis. Despite a significant number of these events being life- and limb-threatening, there is limited evidence on what the appropriate management strategy should be. Evaluation and treatment of any neonate with a clinically significant thrombosis should occur at a tertiary referral center that has proper support.

Hypercoagulability in adolescent girls on oral contraceptives-global coagulation profile and estrogen receptor polymorphisms

Oral contraceptive (OCP) induced changes on coagulation are complex with high inter-individual variability. The precise reason for differences in this variability is unknown. We hypothesized that global coagulation assays better delineate these changes and variability in hypercoagulability may be the result of differences in estrogen metabolism and thrombophilia. Fifty-two adolescents initiating OCPs were prospectively enrolled; 33 subjects completed the study. Samples were analyzed prior to and after OCPs for procoagulant and anticoagulant factor activities and thrombin generation (TG) +/-thrombomodulin. Participants were genotyped for common thrombophilia and estrogen receptor-α (ESR-α) single nucleotide polymorphisms (SNPs). SNP genotypes were compared to coagulation parameters; TG parameters and differences pre and post OCPs were examined. At baseline, a striking finding was elevated FVIII levels. FVL was absent in all and F2 G20210A was present in one participant. The ESR-α polymorphism was present in heterozygous state in 59% and homozygous state in 21% participants. There were no differences in VWF levels and

FVIII

C after being on OCPs. Protein S levels decreased with OCPs. Sixty percent of participants showed evidence of hypercoagulability on TG testing on OCPs. Higher thrombin peak and endogenous thrombin potential (ETP) were seen on TG after OCPs. With thrombomodulin, ETP and thrombin peak did not decrease after OCPs, signifying 'thrombomodulin resistance'. We demonstrated that OCPs induce a state of "variable" hypercoagulability in adolescents, predominantly through the protein S pathway. Genetic and nongenetic factors may account for the variable increase in hypercoagulability. Further research is needed to understand this.

Development of a pediatric-specific clinical probability tool for diagnosis of venous thromboembolism: a feasibility study

BACKGROUND

Pediatric venous thromboembolism (VTE) is an increasingly common, difficult to diagnose problem. Clinical probability tools (CPT) for adults estimate VTE likelihood, but are not available for children. We hypothesized that a pediatric-specific CPT is feasible.

METHODS

Radiology reports were utilized to identify children imaged for suspected VTE. Relevant signs, symptoms, and comorbidity variables, identified from published literature, were extracted from corresponding medical records. Variables associated with pediatric VTE were incorporated into a multivariate logistic regression to create a pilot CPT which was confirmed on a separate cohort.

RESULTS

A total of 389 subjects meeting inclusion criteria were identified: 91 with VTE and 298 without. Univariate analysis revealed male gender (odds ratio (OR) = 2.96; P < 0.001), asymmetric extremity (OR = 1.76; P = 0.033), central venous catheter utilization and/or dysfunction (OR = 2.51; P < 0.001), and cancer (OR = 2.35; P = 0.014) as VTE predictive variables. Documentation of an alternate diagnosis was inversely related to VTE (OR = 0.42; P = 0.004). Receiver operating characteristic analysis of the derived CPT demonstrated reasonable ability to discriminate VTE probability in the training cohort (area under the curve (AUC) = 0.73; P < 0.001) and moderate discrimination in a separate validation cohort of 149 children (AUC = 0.64; P = 0.011).

CONCLUSION

A pediatric-specific VTE CPT is feasible, would facilitate early diagnosis, and could lead to improved outcomes.

Clinical risk factors for central line-associated venous thrombosis in children

BACKGROUND

Identifying risk factors related to central venous line (CVL) placement could potentially minimize central line-associated venous thrombosis (CLAVT). We sought to identify the clinical factors associated with CLAVT in children.

METHODS

Over a 3-year period, 3733 CVLs were placed at a tertiary-care children's hospital. Data were extracted from the electronic medical records of patients with clinical signs and symptoms of venous thromboembolism, diagnosed using Doppler ultrasonography and/or echocardiography. Statistical analyses examined differences in CLAVT occurrence between groups based on patient and CVL characteristics (type, brand, placement site, and hospital unit).

RESULTS

Femoral CVL placement was associated with greater risk for developing CLAVT (OR 11.1, 95% CI 3.9-31.6, p < 0.0001). CVLs placed in the NICU were also associated with increased CLAVT occurrence (OR 5.3, 95% CI 2.1-13.2, p = 0.0003). CVL brand was also significantly associated with risk of CLAVT events.

CONCLUSION

Retrospective analyses identified femoral CVL placement and catheter type as independent risk factors for CLAVT, suggesting increased risks due to mechanical reasons. Placement of CVLs in the NICU also led to an increased risk of CLAVT, suggesting that small infants are at increased risk of thrombotic events. Alternative strategies for CVL placement, thromboprophylaxis, and earlier diagnosis may be important for reducing CLAVT events.

Thrombotic complications in children from short-term percutaneous central venous catheters: what can we do?

The reported incidence of venous thromboembolism (VTE) in children has increased dramatically over the past decade, and the primary risk factor for VTE in neonates and infants is the presence of a central venous catheter (CVC). Although the associated morbidity and mortality are significant, very few trials have been conducted in children to guide clinicians in the prophylaxis, diagnosis, and treatment of CVC-related VTE. Furthermore, pediatric guidelines for prophylaxis and management of VTE are largely extrapolated from adult data. How then should the anesthesiologist approach central access in children of different ages to lessen the risk of CVC-related VTE or in children with prior thrombosis and vessel occlusion? A comprehensive review of the pediatric and adult literature is presented with the goal of assisting anesthesiologists with point-of-care decision-making regarding the risk factors, diagnosis, and treatment of CVC-related VTE. Illustrative cases are also provided to highlight decision-making in varying situations. The only risk factor strongly associated with CVC-related VTE formation in children is the duration of the indwelling CVC. Several other factors show a trend toward altering the incidence of CVC-related VTE formation and may be under the control of the anesthesiologist placing and managing the catheter. In particular, because children with VTE may live decades with its sequelae and chronic vein thrombosis, careful consideration of lessening the risk of VTE is warranted in every child. Further studies are needed to form a clearer understanding of the risk factors, prophylaxis, and management of CVC-related VTE in children and to guide the anesthesiologist in lessening the risk of VTE.

Higher doses of low-molecular-weight heparin (enoxaparin) are needed to achieve target anti-Xa concentrations in critically ill children*

OBJECTIVES

To demonstrate that low-molecular-weight heparin (enoxaparin) can be used in critically ill pediatric patients to achieve target anti-factor Xa concentrations and determine appropriate dosing corrected for age and illness severity.

DESIGN

Retrospective cohort study.

SETTING

Single tertiary level PICU.

PATIENTS

One hundred ninety-two children age 1 day through 18 years admitted to PICU undergoing every 12-hour enoxaparin therapy with at least one anti-factor Xa concentration obtained. Patients receiving renal replacement therapy or infants with corrected gestational age less than 37 weeks were excluded.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We collected patient characteristics including age, weight, height/length, gender, corrected gestational age, illness severity markers, diagnosis, creatinine, enoxaparin dose and times of administration, anti-factor Xa concentrations, and collection times. Only 42% of critically ill children (80 of 192) and only 29% of children (9 of 31) on inotropes achieved recommended target range of anti-factor Xa concentrations on initial recommended enoxaparin dosing (1.5 mg/kg/dose < 2 mo; 1 mg/kg/dose > 2 mo), but 81% were ultimately within target range with dose titration. Increased enoxaparin dose was required to reach target concentrations in younger patients and those with worse illness severity as evidenced by concurrent use of inotropes, previous ICU admission, mechanical ventilation, cardiac surgery, and increased risk of mortality defined by severity-of-illness scores.

CONCLUSIONS

Enoxaparin can be used to reach recommended target range of anti-factor Xa concentrations in the PICU patient. However, younger patients and patients with higher illness severity are less likely to achieve target concentrations using currently recommended dosing and may require higher doses of enoxaparin to reach target anti-factor Xa concentrations. Starting enoxaparin dose at least 1.3 mg/kg dosed every 12 hours for treatment of thromboembolic disease in critically ill patients aged 61 days to 1 year or those requiring inotropic support should be confirmed in prospective study.

Risk factors for hospital-sssociated venous thromboembolism in the neonatal intensive care unit

OBJECTIVE

To determine hospital-associated venous thromboembolism (HA-VTE) risk factors in critically ill neonates.

METHODS

We conducted a case-control study in the neonatal intensive care unit (NICU) of All Children's Hospital Johns Hopkins Medicine (St. Petersburg, FL), from January 1, 2006 - April 10, 2013. We identified HA-VTE cases using electronic health record. Four NICU controls were randomly selected for each HA-VTE case. Associations between putative risk factors and HA-VTE were estimated using odds ratios (ORs) and ninety-five percent confidence intervals (95%CIs) from univariate and multivariate regression analyses.

RESULTS

Twenty-three HA-VTE cases and 92 controls were included. The annual HA-VTE incidence was approximately 1.4 HA-VTE cases per 1,000 NICU admissions. In univariate analyses, mechanical ventilation (OR=7.27, 95%CI=2.02-26.17, P=0.002), central venous catheter (CVC; OR=52.95, 95%CI=6.80-412.71, P<0.001), infection (OR=7.24, 95%CI=2.66-19.72, P<0.001), major surgery (OR=5.60, 95%CI=1.82-17.22, P=0.003) and length of stay ≥15days (OR=6.67, 95%CI=1.85-23.99, P=0.004) were associated with HA-VTE. Only CVC (OR=29.04, 95%CI=3.18-265.26, P=0.003) remained an independent risk factor in the multivariate analysis. Based on this result, the estimated risk of HA-VTE in NICU patients with a CVC was 0.9%.

CONCLUSION

This study identifies CVC as an independent risk factor for HA-VTE in critically ill neonates. However, the level of risk associated with CVC is below the conventional threshold for primary anticoagulation thromboprophylaxis. Larger studies are needed to substantiate these findings and identify novel putative risk factors to further distinguish NICU patients at highest HA-VTE risk.

Retrospective evaluation of antithrombin III supplementation in neonates and infants receiving enoxaparin for treatment of thrombosis

BACKGROUND

Thromboembolic events are occurring at increasing rates in neonates and infants. At Children's Mercy Hospitals and Clinics, antithrombin III (AT3) concentrates are often used in combination with enoxaparin to supplement physiologically low AT3 levels. Theoretically, AT3 enhances the anticoagulant activity of enoxaparin and results in decreased time to therapeutic anti-Xa levels. No data exist on use of AT3 for this indication.

PROCEDURE

This retrospective study compared time to therapeutic anti-Xa levels in patients <1 year of age receiving enoxaparin with AT3 (Group 1) and without AT3 (Group 2) for treatment of thrombosis. Primary objective was to compare time to therapeutic anti-Xa levels (0.5-1 U/ml) between groups. Secondary objectives included comparison of the initial and therapeutic dose of enoxaparin, enoxaparin dose changes, AT3 supplementation, and level monitoring. Bleeding events and cost were also evaluated. Statistical tests included Schuirmann's two one-sided tests for equivalence and general linear models/logistic regression for independent effects of age, critical illness, and timing of AT3.

RESULTS

Mean time to therapeutic anti-Xa levels were not equivalent between Groups 1 and 2 (80.7 vs. 65.2 hours; P = 0.28). Initial enoxaparin dose and number of dose changes were equivalent. Group 1 required higher doses of enoxaparin to achieve therapeutic anti-Xa levels. Age, critical illness, and timing of AT3 had no effect on time to therapeutic anti-Xa levels. Bleeding events were not equivalent between Groups 1 and 2 (14.3% vs. 3.9%; P = 0.55).

CONCLUSION

Supplementation with AT3 did not decrease time to therapeutic anti-Xa levels, added significant cost, and was associated with increased bleeding events.

Venous thromboembolism in pediatric nephrotic syndrome

Childhood nephrotic syndrome (NS) is one of the most common pediatric kidney diseases, with an incidence of 2-7 per 100,000. Venous thromboembolism (VTE) is associated with significant morbidity and mortality, and occurs in ∼3 % of children with NS, though incidence approaches 25 % in high-risk groups. VTE etiology is multifactorial, with disease-associated coagulopathy thought to be a significant contributor. Other risks include age, disease severity, and treatment-related hazards, such as the presence of central venous catheters. Non-pharmacologic preventive measures such as ambulation and compression stockings are recommended for patients with identified VTE risks. Central venous catheters should be avoided whenever possible. Symptoms of VTE include venous catheter dysfunction, unilateral extremity symptoms, respiratory compromise, flank pain, and gross hematuria. When VTE is suspected, confirmatory imaging studies should be obtained, followed by appropriate laboratory evaluation and treatment. Therapeutic goals include limiting thrombus growth, extension, and embolization by early institution of anticoagulant therapy. Anticoagulation is recommended for a minimum of 3 months, but should be continued until NS remission is achieved. Further studies are necessary to identify VTE-risk biomarkers and optimal therapeutic regimens. Observational cohort studies are needed to identify VTE-risk groups who may benefit from thromboprophylaxis and to define disease-specific treatment algorithms.

Alterations in the Coagulation System during Major Visceral Surgery in Children

Purpose. The description of the alterations in the hemostatic system in children undergoing abdominal surgery is sparse. Enhanced clinical outcomes for previously untreatable conditions have led to an increased incidence of venous thromboembolic complications. Alterations in children's coagulation system during major abdominal operations compared to minor procedures were examined. Methods. Children (0–12 years) undergoing either laparotomy, thoracotomy, or minor surgery were included. Participants were divided into two groups: group 1 was open laparotomy including operations for solid abdominal tumours and thoracotomy, while group 2 was minor surgery. Activated partial thromboplastin time (aPTT), D-dimer, INR, and fibrinogen were measured. Results. Both groups had a shorter aPTT, higher INR, and lower fibrinogen concentrations after the operation, while D-dimer was unaltered. The changes were, however, discrete and probably not clinically significant. On day 3, all parameters except aPTT in group 1 (not measured in group 2) indicated a continuous coagulation activity. Conclusion. The tendency for coagulation activity altered based on the length and degree of surgery. A continuously altered activity was observed compatible with the reported increased risk of venous thromboembolism at day 3. However, before introducing thromboprophylaxis guidelines larger series of multicentre studies are needed.

Survey results: characterization of direct thrombin inhibitor use in pediatric patients

OBJECTIVES

The objective of this multicenter survey is to characterize the use of direct thrombin inhibitors (DTIs) in the pediatric population. The results of this survey may be used to design a prospective multicenter study with the ultimate goal of developing a dosing/titration recommendation for the use of DTIs in the pediatric population.

METHODS

This is a multicenter, descriptive study to survey hospitals around the country regarding the use of DTIs (argatroban, bivalirudin, and lepirudin) in the pediatic population. Institutional review board approval was obtained. The survey consisted of 42 questions and was designed utilizing Survey Monkey. The survey was emailed to members of the Pediatric Pharmacy Advocacy Group. Listserv members who responded to the survey within 4 weeks of when the survey was emailed were included in the study. Descriptive statistics were performed utilizing Microsoft Excel 2007.

RESULTS

Responses were obtained from 56 institutions from 29 states in the United States. Multiple agents are available on formulary with argatroban being the most common (~80%). The large majority of institutions (41.1%) utilize DTIs 2 to 4 times a year with an additional 33.9% utilizing them less than twice a year. There is no consistent approach to dosing and titration amongst pediatric institutions.

CONCLUSIONS

There are a wide variety of methods used by pediatric institutions with regard to dosing and titration of DTIs. Recently published prospective studies and package insert updates should help guide practitioners toward a more consistent approach to dosing of these high-risk medications.

Dosing and monitoring of enoxaparin therapy in children: experience in a tertiary care hospital

Pediatric deep vein thrombosis (DVT) is an emerging problem in tertiary care hospitals, recent reviews shows a rate of 40.2/10,000 admissions. Experts affirm that enoxaparin has become in the drug of choice for DVT therapy. Despite this, there is a little information regarding the optimal dose schedule for enoxaparin therapy in children and the therapeutic guidelines for enoxaparin use in children are extrapolated from adult guidelines. Monitoring by antifactor Xa (anti-Xa) measurement and target concentrations between 0.5-1 U/ml at 4-6 h postdose are recommended. This study was designed to analyse our experience in paediatric-specific dosage requirements for enoxaparin therapy. A retrospective study was performed with patients less than 16 years old, who were treated with enoxaparin for DVT and monitored by anti-Xa concentration, between January 2005 and March 2012. Demographic and clinical characteristics and outcomes were obtained. Fourteen patients were analyzed: boy/girl ratio, 8/4; median age, 3.5 months. Cerebral venous sinus thrombosis was the most common indication for therapy. All patients presented thrombosis risks factors. Dose increases were necessary only in patients less than 6 years old. Target anti-Xa concentrations were achieved in 12 (85%) patients. Children younger than 1 year required a higher dose of enoxaparin/kg (1.5-2.7 mg/kg per 12 h). Complete resolutions of DVT were registered in all cases. The mean number of dose increases was three and a median of 11 days to achieve target anti-Xa concentration. This study indicates that an initial higher enoxaparin dose may be necessary in neonates and infants, but other factors must be considered to improve management.

Neonatal and infant pulmonary thromboembolism: a literature review

Pulmonary thromboembolism (PTE) is rare in neonates and infants; however evidence suggests it is underdiagnosed. The primary objective is to conduct a scientific review to determine if the presentation, diagnosis, treatment and outcomes of neonates and infants with PTE are consistent across studies. Secondly, to develop an algorithm to establish the diagnosis and management of the condition based on current information. Two authors searched the literature independently using existing databases and verified that identical articles were assembled. Infants aged less than 1 year with PTE were included and further categorized into neonates 28 days or less and infants 29 days to 1 year or less. Forty-five articles with 157 cases (121 neonates; 36 infants) were identified with PTE. All of the reports were descriptive and neither randomized controlled trials nor prospective or case-control studies were identified. The reports are sub-classified into cases of pulmonary air embolism (PAE) with a higher mortality rate and patients with PTE. Diagnostic and treatment strategies varied widely and were individually case-based, dependent on clinical findings, which influenced patient outcomes. Scientific data to guide an evidence-based, diagnostic and treatment approach to PTE is limited because of the absence of rigorous clinical trials. Large scale, multicenter collaborative studies are required to firmly establish the management of PTE in this population.

Evaluation of the use of low-molecular-weight heparin in neonates: a retrospective, single-center study

Controversies exist over the currently recommended guidelines for the use of low-molecular-weight heparin (LMWH) in neonates. We retrospectively studied 30 neonates treated with LMWH and found a poor therapeutic response to recommended doses as measured by anti-Xa levels. Sixty percent of the study participants required their doses to be increased because of subtherapeutic anti-Xa levels during the initial course of their treatment. The mean starting enoxaparin dose was 1.53 ± 0.38 mg/kg. The mean enoxaparin dose, once therapeutic anti-Xa levels had been achieved, was 1.86 ± 0.50 mg/kg. Preterm and term infants required doses of 2.06 ± 0.61 mg/kg and 1.67 ± 0.26 mg/kg, respectively, to achieve therapeutic anti-Xa levels. In summary, our results suggest that higher initial doses are required to achieve therapeutic anticoagulation in neonates.

Characteristics of abdominal vein thrombosis in children and adults

The demographic and clinical characteristics of adults and children with lower extremity deep-vein thrombosis and/or pulmonary embolism (LE DVT/PE) may differ from those with abdominal vein thrombosis (abdominal VT). Abdominal VT can be a presenting sign of an underlying prothrombotic state, and its presence in the setting of known disease might have prognostic implications different from LE DVT/PE. This study describes clinical presentations of abdominal VT compared to LE DVT/PE in adults and children. We analysed prospectively-collected data from consecutive consenting patients enrolled in one of seven Centers for Disease Control and Prevention (CDC) funded Thrombosis and Hemostasis Network Centers from August 2003 to April 2011 to compare the demographic and clinical characteristics of adults and children with abdominal VT. Both adults and children with abdominal VT tended to be younger and have a lower body mass index (BMI) than those with LE DVT/PE. Of patients with abdominal VT, children were more likely to have inferior vena cava (IVC) thrombosis than adults. For adults with venous thromboembolism (VTE), relatively more women had abdominal VT than LE DVT/PE, while the proportions with LE DVT/PE and abdominal VT by sex were similar in children. Children with abdominal VT were more likely to have diagnosed inherited thrombophilia, while trauma was more common in children with LE DVT/PE. In conclusion, both children and adults with abdominal VT were younger with a lower BMI than those with LE DVT/PE. Significant differences exist between children and adults in respect to abdominal VT compared to LE DVT/PE.