A cross-sectional study evaluating post-thrombotic syndrome in children

Incidence of acute Deep Vein Thrombosis in pediatric and adolescent orthopedic trauma hospitalized patients and effect of rivaroxaban treatment

OBJECTIVE

Deep vein thrombosis (DVT) provoked by orthopedic trauma is increasing in pediatric hospitalized patients. The purpose of our study is to identify the prevalence of acute DVT in pediatric and adolescent orthopedic trauma hospitalized patients and focus on evaluating the anticoagulation strategies and the clinical outcomes after a confirmed acute DVT.

METHODS

Patients (age ≤18 years) with a confirmed acute DVT admitted for orthopedic trauma between September 2017 and December 2023 were included. Patients were classified into the non-anticoagulation (NA), the in-hospital anticoagulation (IHA), and the in-and-out-of-hospital anticoagulation (IOHA) groups based on their anticoagulation regimen. Efficacy outcomes were the venous thromboembolism (VTE) recurrence within 3 months and change in thrombus burden by repeat imaging at 2 weeks after discharge compared with baseline. Safety outcomes were major bleeding (MB) and clinically relevant non-major bleeding (CRNMB) within 3 months.

RESULTS

Of the 11,206 pediatric and adolescent orthopedic trauma inpatients, 94(median age,16 [15, 18] years) were diagnosed with acute DVT, with an incidence of 0.84 %, of which 8(8.5 %) received NA, 41(43.6 %) received IHA, and 45(47.9 %) received IOHA. After the diagnosis of DVT, of patients who received anticoagulation, 97.9 % were treated with rivaroxaban as an oral anticoagulant, and 71.7 % received an LMWH course of ≥5 days before starting rivaroxaban therapy. With a median anticoagulation course of 22(8, 37.3) days, the duration in the IOHA was significantly longer than the IHA (37 days vs. 8 days, p = 0.000). No patients experienced recurrent VTE and MB at 3 months, and 1 received IOHA had a CRNMB event (0 % vs. 0 % vs. 2.2 %, p = 1.000). Thrombus resolution was significantly higher in patients who received anticoagulation therapy (IOHA 91.1 % vs. IHA 80.5 % vs. NA 37.5 %, P = 0.002), and thrombus-no relevant change was significantly lower in patients who received the IOHA strategy compared with the other groups (4.4 % vs. 19.5 % vs. 62.5 %, P = 0.000).

CONCLUSIONS

A rivaroxaban-predominant IOHA strategy significantly reduced the thrombotic burden without increasing the risk of bleeding for the treatment of DVT in adolescents with orthopedic trauma. Duration of anticoagulation therapy <6 weeks appears appropriate for adolescent orthopedic trauma-related DVT.

Sequelae and post-thrombotic syndrome after venous thromboembolism in acute lymphoblastic leukemia survivors treated on the NOPHO ALL2008 protocol

The treatment of acute lymphoblastic leukemia (ALL) is frequently complicated by toxicity, including venous thromboembolism (VTE) affecting roughly 8% of patients. VTE can lead to post-thrombotic syndrome (PTS), a group of signs and symptoms developed as a complication to deep venous thrombosis (DVT), imposing risk of permanent disability and reduced quality of life (QoL). PTS prevalence ranges from 0% to 70%, reflecting very heterogenous cohorts and assessment tools. We aimed to estimate sequelae, including PTS and QoL in children and adults (<45 years old) who had a DVT during ALL treatment. PTS and QoL scores were obtained through use of Villalta and Modified Villalta Scale, PedsQL, and Short Form-36 questionnaires. The cohort comprised 20 children (<18 years) and seven adults (median age: 12.9 years, range: 2-44 years) at the time of DVT diagnosis. In total, 25 ALL survivors underwent PTS examination. The examination took place when survivors were 7-48 years (median age: 20.3 years, median follow-up time 6.8 years). QoL was assessed correlating cases with three matching ALL survivors without VTE. Two adults (15.4%) showed mild or moderate PTS. Eight children (66.7%) were diagnosed with mild PTS, while three cases had collaterals as sole symptoms. Pain or symptoms affecting daily life were reported by 16%. No difference in QoL was found (p = .9). This study underscores the need for comprehensive population-based investigations with validation of PTS instruments in ALL survivors.

Updated guidance for efficacy and safety outcomes for clinical trials in venous thromboembolism in children: communication from the ISTH SSC Subcommittee on Pediatric and Neonatal Thrombosis and Hemostasis

Despite the growing number of pediatric antithrombotic clinical trials, standardized safety and efficacy outcome definitions for pediatric venous thromboembolism (VTE) clinical trials have not been updated since 2011. Many recent trials have adapted the recommended definitions, leading to heterogeneity in outcomes and limiting our ability to compare studies. The International Society on Thrombosis and Haemostasis Scientific and Standardization Subcommittee (SSC) on Pediatric and Neonatal Thrombosis and Hemostasis organized a Task Force to update the efficacy and safety outcome definitions for pediatric VTE clinical trials. The outcome definitions used in the recent pediatric antithrombotic trials, definitions recommended for adult studies, and regulatory guidelines were summarized and reviewed by the Task Force as the basis for this updated guidance. Major updates to the efficacy outcomes include the removal of VTE-related mortality as a part of a composite primary outcome and explicit inclusion of all deep venous anatomic sites. Safety outcomes were updated to include a new bleeding severity category: patient important bleeding, no intervention, which encompasses bleeding for which a patient seeks care but there is no change in management. Menstrual bleeding can now be included in any bleeding category when the criteria are met. We hope that these updated outcome definitions will allow the investigators to focus on clinically relevant and patient-important outcomes and provide standardization to facilitate continued high-quality evidence for the use of antithrombotic therapies in children.

Society of Interventional Radiology Position Statement on the Endovascular Management of Acute Iliofemoral Deep Vein Thrombosis

PURPOSE

To establish the updated position of the Society of Interventional Radiology (SIR) on the endovascular management of acute iliofemoral deep vein thrombosis (DVT).

MATERIALS AND METHODS

A multidisciplinary writing group with expertise in treating venous diseases was convened by SIR. A comprehensive literature search was conducted to identify studies on the topic of interest. Recommendations were drafted and graded according to the updated SIR evidence grading system. A modified Delphi technique was used to achieve consensus agreement on the recommendation statements.

RESULTS

A total of 84 studies, including randomized trials, systematic reviews and meta-analyses, prospective single-arm studies, and retrospective studies were identified and included in the review. The expert writing group developed 17 recommendations that pertain to the care of patients with acute iliofemoral DVT with the use of endovascular venous interventions.

CONCLUSIONS

SIR considers endovascular thrombus removal to be an acceptable treatment option in selected patients with acute iliofemoral DVT. Careful individualized risk assessment, high-quality general DVT care, and close monitoring during and after procedures should be provided.

Use and Misuse of Parenteral Nutrition in Patients with Inflammatory Bowel Disease

Malnutrition is a very common and often underrecognized condition among patients with inflammatory bowel diseases (IBD). This is most commonly due to increased nutritional requirements and gastrointestinal losses, along with reduced oral intake. Screening for malnutrition is an essential component of managing both inpatients and outpatients with IBD. Although enteral nutrition is the preferred route of supplementation, parenteral nutrition (PN) remains an important strategy and should be considered in certain situations, such as cases with short-bowel syndrome, high-output intestinal fistula, prolonged ileus, or small-bowel obstruction. Appropriate use of PN is critical in order to prevent associated complications. This review addresses the common indications for use of PN, the composition of PN, and the possible complications encountered with PN use, as well as scenarios of inappropriate PN use among patients with IBD. A clinical management algorithm for utilizing PN among patients with IBD is proposed in this review.

Successful Secondary Endovascular Intervention in Pediatric Patients with Venous Thromboembolic Events

BACKGROUND

 In the past, pediatric patients with venous thromboembolic events (VTE) were treated with low-molecular-weight heparin (LMWH) which was successful in around 70% of the cases. However, anticoagulation alone might not restore patency in all patients, and advanced therapeutic options to prevent postthrombotic syndrome are needed. During recent years, endovascular interventions have become a treatment option for pediatric patients with persistent thrombotic occlusion, not only in life- or limb-threatening VTE.

METHODS

 We evaluated 12 consecutive patients (11-17 years) with newly diagnosed VTE being treated at our department during the last 4 years (2017-2020). In case follow-up examination showed persistent venoocclusion under anticoagulation, patients received secondary interventional therapy like recanalization, percutaneous transluminal angioplasty with or without catheter-directed thrombolysis, and stenting. Patients with no clinical signs of venoocclusion or regredient thrombosis in imaging examination received anticoagulation alone.

RESULTS

 Six of 12 (50%) patients underwent catheter intervention. Median time from diagnosis to intervention was 4 months (0-12 months). Reintervention was necessary in one (8%) case and complete recanalization failed in one (8%) case. There were no major bleeding events or other major postinterventional complications, no acute or late local recurrence, and all patients reported clinical improvement after the procedure.

CONCLUSION

 If endovascular intervention is used in teenage patients with persistent symptomatic VTE, reduction of postthrombotic symptoms is possible, even if intervention is performed secondary to failure of anticoagulation. Multidisciplinary treatment decisions can be based on the clinical course and follow-up imaging.

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.

Venous thoracic outlet syndrome and Paget-Schroetter syndrome

Venous thoracic outlet syndrome represents a relatively rare but important diagnosis in the adolescent population with increasing recognition. Compression of the subclavian vein within the costoclavicular space can lead to episodic venous outlet obstruction in the upper extremity, with edema, rubor and functional symptoms. Over time, cumulative injury and compression can lead to thrombosis of the vein, referred to as "effort thrombosis" or the Paget-Schroetter syndrome. This progression can lead to the need for acute management of the venous thromboembolism, requirement for thoracic outlet decompression surgery and the potential for long-term sequelae such as post-thrombotic syndrome. Management is focused on clot minimization, anticoagulation during the period of endothelial injury and inflammation and surgical decompression via first rib resection, anterior scalenectomy and venolysis to remove external compression of the vein. This manuscript reviews the diagnosis, evaluation and treatment of venous thoracic outlet syndrome and Paget-Schroetter syndrome.

Risk factors determining central venous access device-associated deep vein thrombosis resolution in children: a retrospective study

The risk factors associated with the probability of central venous access device (CVAD)-associated deep vein thrombosis (DVT) resolution have been hardly evaluated in children. Current guidelines suggest anticoagulation for a maximum of 3 months in patients with provoked DVT if the provoking factor is resolved. To know if the thrombus will resolve after anticoagulant therapy will help to choose whether to initiate and/or continue this treatment or not. We did a retrospective study of 85 pediatric patients (45 girls, 40 boys) with CVAD-associated DVT to examine the risk factors associated with lack of thrombus resolution in the first 6 months after diagnosis. Sixty-two children had their thrombosis resolved after a median of 50 days (p25-p75 25-97) since diagnosis. In multivariate analysis, variables significantly associated with no resolution were total occlusion (OR 12.50, 95% CI 2.99-52.14, p=.001), location in upper extremity, head, and neck veins (OR 17.70, 95% CI 1.64-191.43, p=.018); collateral circulation in the first 45 days after diagnosis (OR 33.55, 95% CI 2.42-464.71, p=.009); and having between 0 and 3 prothrombotic risk factors at diagnosis (OR 6.20, 95% CI 1.21-31.75, p=.029).Conclusion: CVAD-associated DVT resolution in children in the first 6 months since diagnosis was significantly lower if the thrombosis was occlusive, if it was located in the upper extremity, head, and neck veins; if collateral circulation was seen on ultrasound in the first 45 days; and/or when the patient showed less prothrombotic risk factors at diagnosis. What is Known: • The risk factors associated with central venous access device-associated deep vein thrombosis resolution have been hardly evaluated in children. • Current guidelines suggest anticoagulation for a maximum of 3 months in provoked vein thrombosis if the provoking factor is resolved. What is New: • Thrombus resolution was lower if it was occlusive, located in the upper extremity veins, if collateral circulation was seen, and with less prothrombotic risk factors at diagnosis. • To know if the thrombus will resolve after anticoagulation will help to choose whether to initiate and/or continue it or not.

Venous Thromboembolism among Critically Ill Children: A Narrative Review

Venous thromboembolism (VTE) is a leading cause of morbidity and mortality among hospitalized patients, including children. In recent years, it has become clear that hospitalization and critical illness bestow an increased VTE risk in pediatrics and relate to mortality and life-limiting comorbidities. For critically ill children, reported rates of VTE vary by study sampling techniques, presence of inherited or acquired thrombophilia, acute and chronic immobility, underlying illness prompting hospitalization, and clinical factors related to illness severity such as central venous catheterization, length of stay, mechanical ventilation, and patient age. Accordingly, critically ill children with new signs of venous congestion, acute inflammation, or unexplained acute organ dysfunction should be routinely evaluated for VTE. This narrative review summarizes recent and historical literature regarding risk factors, prevention, presentation, treatment, and outcomes of VTE in critically ill children. In addition, we identify knowledge gaps and priorities for future collaborative research on this vital condition. Special attention is given to the clinical trial opportunities, challenges, and ongoing efforts in thromboprophylaxis in critically ill children, including those hospitalized for disease related to novel coronavirus (COVID-19) and multisystem inflammatory disease in children.

Diagnosis, Clinical Characteristics, and Treatment Modalities of Adolescent May-Thurner Syndrome-associated Deep Venous Thrombosis

May-Thurner syndrome (MTS) predisposes individuals to develop lower extremity deep venous thrombosis (DVT) because of compression of the left common iliac vein. Diagnosis of the anatomic obstruction is critical for effective therapy, as treatment by interventional radiology is often required in addition to anticoagulation to prevent thrombus progression and recurrence. The authors performed a retrospective review of adolescent patients who presented with MTS-associated DVT at a pediatric tertiary care center from 2009 to 2018 to assess for delays in MTS diagnosis after the presentation. Fourteen patients (median age 16.5 y, range, 13.8 to 17.9 y) were included, no DVTs were provoked by a central venous catheter. The median time from DVT to MTS diagnosis was 0.65 months (range, 0 to 21.5 mo). The initial imaging modalities used for DVT diagnosis were not able to diagnosis MTS. All patients were treated with anticoagulation and 13 underwent interventional therapy. Four patients had thrombus progression or recurrence, whereas 6 had complete thrombus resolution on follow-up imaging. Three patients who had a delayed MTS diagnosis had clinical worsening despite therapeutic anticoagulation requiring rehospitalization. Adolescent patients with "unprovoked" left lower extremity DVT should undergo appropriate imaging to diagnose MTS to allow for adequate medical and interventional therapy.

Validation of Outcome Instruments for Pediatric Postthrombotic Syndrome: Introducing the Peds-VEINES-QOL, a New Health-Related Quality of Life Instrument

BACKGROUND

 There is need for validated outcome measures for postthrombotic syndrome (PTS) following pediatric venous thromboembolism (VTE), with a focus on quality of life (QoL).

AIMS

 This article assesses reliability and validity of two PTS and two QoL scales for children following lower extremity VTE.

METHODS

 Pediatric patients following lower extremity VTE were recruited from three thrombosis clinics. The Manco-Johnson (MJ) and the modified Villalta (MV) PTS scales were compared with each other and with the generic pediatric health-related QoL, PedsQL, and a newly developed pediatric venous-specific QoL, the Peds-VEINES-QOL.

RESULTS

 Eighty children following VTE and 60 healthy control children were enrolled. Internal consistency measured by Cronbach's α was high for the two QoL scales, and moderate for the two PTS scales. Inter-rater reliability using intraclass correlation coefficients was moderate to high for the MJ, MV, and Peds-VEINES-QOL, and moderate for the PedsQL. Evidence of high internal consistency by Cronbach's α coefficients, and moderate to high interitem correlations support the premise that a single construct was measured by each instrument. Correlations between the four instruments indicate convergent validity.

CONCLUSION

 The MJ and MV scales detect similar outcomes in children following VTE. As used, the MJ is slightly more sensitive to QoL because a positive diagnosis requires pain which is the leading factor in reduced QoL following deep vein thrombosis. When using the MV, a requirement for pain or abnormal use to diagnose PTS would make the MV a better predictor of QoL.

The survival benefit of low molecular weight heparin over unfractionated heparin in pediatric trauma patients

INTRODUCTION

Venous thromboembolism (VTE) prophylaxis in pediatric patients is controversial and is mainly dependent on protocols derived from adult practices. Our study aimed to compare outcomes among pediatric trauma patients who received low molecular weight heparin (LMWH) compared to those who received unfractionated heparin (UFH).

METHODS

We performed 2 years (2015-2016) retrospective analysis of the Pediatrics ACS-TQIP database. Pediatric trauma patients (age ≤17) who received thromboprophylaxis with either LMWH or UFH were included. Patients were stratified into three age groups. Analysis of each subgroup and the entire cohort was performed. Outcome measures included VTE events (deep vein thrombosis [DVT] and pulmonary embolism [PE]), hospital and ICU length of stay (LOS) among survivors, and mortality. Propensity score matching was used to match the two cohorts LMWH vs UFH.

RESULTS

A matched cohort of 1,678 pediatric trauma patients was analyzed. A significant difference in survival, DVT events, and in-hospital LOS was seen in the age groups above 9 years. Overall, the patients who received LMWH had lower mortality (1.4% vs 3.6%, p<0.01), DVT (1.7% vs 3.7%, p<0.01), and hospital LOS among survivors (7 days vs 9 days, p<0.01) compared to those who received UFH. There was no significant difference in the ICU LOS among survivors and the incidence of PE between the two groups.

CONCLUSION

LMWH is associated with increased survival, lower rates of DVT, and decreased hospital LOS compared to UFH among pediatric trauma patients age 10-17 years.

LEVEL OF EVIDENCE

Level III Prophylactic.

STUDY TYPE

Prophylactic.

The Edoxaban Hokusai VTE PEDIATRICS Study: An open-label, multicenter, randomized study of edoxaban for pediatric venous thromboembolic disease

BACKGROUND

Little evidence is available for treatment of pediatric venous thromboembolism (VTE). Large randomized controlled trials are challenging in children. Current antithrombotic agents have many limitations, including nonoral administration and frequent monitoring. Edoxaban is an oral direct inhibitor of factor Xa without need of monitoring. In adults with VTE, edoxaban has shown to be effective and safe.

OBJECTIVES

The Edoxaban Hokusai VTE PEDIATRICS Study is an open-label, randomized clinical trial to evaluate pharmacokinetics (PK) and pharmacodynamics (PD) of edoxaban and whether edoxaban is noninferior to standard of care in treatment of pediatric VTE.

METHODS

A goal of 274 patients will be recruited in 5 age categories. A multidose PK/PD assessment on day 5 in the first 12 patients of each age group is incorporated into this study. The primary composite efficacy outcome comprises symptomatic recurrent VTE, death due to VTE, and no change or extension of thrombotic burden. The principal safety end point is a combination of major and clinically relevant nonmajor bleeding. PK end points include apparent systemic clearance and volume of distribution of edoxaban. PD end points include prothrombin time, activated partial thromboplastin time, and anti-factor Xa level for the edoxaban treatment arm.

RESULTS

To increase feasibility, the multidose PK/PD study is integrated in the phase 3 trial. In addition, thrombotic burden, which is a prognostic factor for post thrombotic syndrome in children, is one of the components of the primary composite efficacy outcome.

CONCLUSION

This study will increase the level of evidence for treatment in pediatric VTE.

A review into the management of May-Thurner syndrome in adolescents

OBJECTIVE

To investigate the presentation, etiology, management and outcomes of May-Thurner syndrome (MTS) in adolescents aged under 18.

METHODS

We searched electronic bibliographic databases to identify published reports of MTS in patients under 18 years of age. We conducted our review according to the PRISMA statement standards.

RESULTS

Ten studies encompassing 22 patients treated for MTS in adolescent cases were identified. The mean age of patients was 15 years (range, 10-18 years). Of the 22 patients, 12 (55%) were confirmed to have proximal deep vein thrombosis as the primary indication for intervention. Treatment methods included catheter-directed thrombolysis and iliac vein stenting (41%), pharmacomechanical thrombolysis and iliac vein stenting (18%), iliac vein stenting alone (27%), open surgery (14%), catheter-directed thrombolysis (5%), and anticoagulation alone (5%). Complications were infrequent. All studies reported subjective improvements in clinical symptoms with only two studies using validate outcome measures. In total, 9 of 22 patients (41%) had addition risk factors that may precipitate thrombosis.

CONCLUSIONS

As in adults, the most common form of treatment seen in the literature is a combination of catheter direct thrombolysis, followed by iliac vein stenting with subsequent anticoagulation. Complications from interventions were low. It is unclear how these interventions affect symptomology and the long-term sequalae associated endovascular surgery and stenting in adolescents. Further research is needed in well-designed studies with adequate follow-up.

A retrospective analysis of risk factors associated with catheter-related thrombosis: a single-center study

BACKGROUND

Catheter-related thrombosis may lead to catheter infections and failure, further deep venous thrombosis, and pulmonary embolism. Recognizing the risk factors for catheter-related thrombosis is extremely important to inform the development of catheter care guidelines.

METHODS

Data were collected from a total of 1,532 patients who had undergone venous catheterization, including indwelling catheterization from 19 March 2019 to 30 March 2019 in the Sun Yat-sen Memorial Hospital. The factors for which data were to be collected included the patients' physical characteristics, catheter-related factors, and catheter care-related factors. Logistic regression analysis, the chi-squared test, Fisher's exact test, and the t-test were used to analyze the data.

RESULTS

Of the 1,532 patients studied, 28 developed intraductal thrombi, and of the factors analyzed, malignancy, a catheterization history, a history of thrombophilia, surgery during the week before catheterization, the catheterization duration, and anticoagulant therapy were significant risk factors associated with catheter-related thrombosis (all p < 0.05). There were no significant associations between the catheter brand, the number of lumens, the insertion direction, or the factors associated with catheter care and catheter-related thrombosis (all p > 0.05).

CONCLUSION

Our study incorporated clear and systematic risk factors associated with catheter-related thrombosis. Malignancy, history of thrombophilia, history of catheterization, surgery during the week before catheterization, and catheterization duration were associated with increased risks of catheter-related thrombosis. Prophylactic anticoagulation was effective for preventing and treating catheter-related thrombosis.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSION

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

Post-thrombotic syndrome in children: Measurement properties of CAPTSure, a new diagnostic tool

BACKGROUND

CAPTsure (Clinical Assessment of PTS) is a new tool for diagnosis and severity rating of pediatric postthrombotic syndrome (PTS). Our objective was to test the reliability, measurement error, and minimal detectable change of CAPTSure.

METHODS

Children aged newborn to 18 years who sustained upper extremity or lower extremity deep vein thrombosis (DVT) were enrolled ≥ 6 months after DVT diagnosis. Patients were assessed by 2 raters to determine the reliability of the clinician assessment component (CC) of CAPTSure. Patients/proxies completed CAPTSure at baseline and approximately 2 weeks later to assess test-retest reliability of the symptoms component (SC).

RESULTS

Of 148 patients enrolled in the study; 30 had sustained either bilateral or both upper and lower extremity DVT. Hence, 178 extremities were assessed for PTS signs (86 upper extremity, 92 lower extremity). Intraclass correlation coefficient (ICC) for the CC was 0.89 (95% confidence interval [CI], 0.84-0.93) for upper extremity and 0.88 (95% CI, 0.83-0.92) for lower extremity. Nonclinicians performed 59% of measurements. Ninety-eight patients completed the SC at baseline and follow-up, for a total of 60 upper extremity and 61 lower extremity assessments. ICC for the SC was 0.89 (95% CI, 0.84-0.93) for upper extremity and 0.92 (0.87-0.95) for lower extremity. ICC for CAPTSure was 0.92 (95% CI, 0.87-0.95) for upper extremity and 0.93 (95% CI, 0.88-0.95) for lower extremity assessment. Measurement error ranged between 1.7 and 4.3 of 100 points. A change of approximately 11 of 100 points in CAPTSure score would be required to be confident that there was a change in PTS severity.

CONCLUSION

CAPTSure has excellent reliability and a small measurement error, even when applied by nonhematologists.

Central Venous Catheter-Related Deep Vein Thrombosis in the Pediatric Cardiac Intensive Care Unit

BACKGROUND

Central venous catheter (CVC) use is common in the management of critically ill children, especially those with congenital heart disease. CVCs are known to augment the risk of deep vein thrombosis (DVT), but data on CVC-associated DVTs in the pediatric cardiac intensive care unit (CICU) are limited. In this study, we aim to identify the incidence of and risk factors for CVC-related DVT in this high-risk population, as its complications are highly morbid.

MATERIALS AND METHODS

The PC4 database and a radiologic imaging database were retrospectively reviewed for the demographics and outcomes of patients admitted to the Texas Children's Hospital CICU requiring CVC placement, as well as the incidence of DVT and its complications.

RESULTS

Between January 2017 and December 2017, 1215 central lines were placed over 851 admissions. DVT was diagnosed in 8% of admissions with a CVC, 29% of which demonstrated thrombus in the inferior vena cava. The risk factors significantly associated with DVT included the presence of >1 line, higher total line hours, longer intubation times, and extended CICU stay. A diagnosis of low cardiac output syndrome, sepsis, central line-associated bloodstream infection, and cardiac catheterization were also significant risk factors. Interestingly, cardiac surgery with cardiopulmonary bypass appeared to be protective of clot development. DVT was a highly significant risk factor for mortality in these patients.

CONCLUSIONS

CVC-related DVTs in critically ill children with congenital heart disease are associated with higher risks of morbidity and mortality, highlighting the need for well-designed studies to determine the best preventative and treatment strategies and to establish guidelines for appropriate monitoring and follow-up of these patients.

Treatment-Related Outcomes in Paget-Schroetter Syndrome-A Cross-Sectional Investigation

OBJECTIVE

To investigate treatment-related outcomes, namely radiological clot resolution, post-thrombotic syndrome (PTS), and health related quality-of-life (HRQoL) scores, in children with Paget-Schroetter syndrome (PSS) undergoing multidisciplinary management, including anticoagulation and decompressive rib-resection surgery, with or without thrombolytic therapy.

STUDY DESIGN

We identified all patients treated for PSS at our institution between the years 2010 and 2017. Baseline clinical and radiologic data were abstracted from medical records. Two validated survey instruments to quantify PTS and HRQoL were mailed to eligible patients. Standard statistical methods were used to summarize these measures.

RESULTS

In total, 22 eligible patients were identified; 10 were treated with thrombolysis followed by anticoagulation and rib resection, and 12 were treated with anticoagulation and rib resection alone. Nineteen patients responded to the survey instruments. Median age at deep vein thrombosis diagnosis and survey completion were 16.3 and 20.4 years, respectively. Nineteen of 22 patients had thrombus resolution on radiologic follow-up. Fourteen of 19 survey respondents reported signs/symptoms of PTS of which the majority (12/14) reported mild PTS. Aggregate total, physical, and psychosocial HRQoL scores reported were 90.6, 96.7, and 93.3, respectively. Thrombolytic therapy was not associated with a significant improvement in radiologic, clinical or HRQoL outcomes.

CONCLUSIONS

Most patients with PSS had complete thrombus resolution on imaging. Only 11% of survey respondents reported moderate PTS. The entire cohort reported excellent HRQoL scores. The role for thrombolytic therapy in the management of childhood PSS remains incompletely elucidated.

Characterization of Post-Thrombotic Syndrome in Children with Cardiac Disease

OBJECTIVE

To assess the validity of existing clinical scales assessing the presence of physical and functional abnormalities for diagnosing post-thrombotic syndrome (PTS) in children, including specific evaluation of use in children with congenital heart disease (CHD).

STUDY DESIGN

One hundred children aged >2 years (average age, 6 years), including 33 with CHD and previously proven extremity deep vein thrombosis (DVT), 37 with CHD and no previous DVT, and 30 healthy siblings, were blindly assessed for PTS using the modified Villalta Scale (MVS). All patients aged <6 years underwent neurodevelopmental testing and an age-appropriate quality of life assessment.

RESULTS

The MVS identified mild PTS in 20 children and moderate PTS in 1 child (including 14 of 33 [42%] in the CHD/DVT group, 5 of 37 [14%] in the CHD/no DVT group, and 2 of 30 controls [7%]). The diagnosis of PTS was confirmed clinically in 14 patients, all of whom had previous thrombosis and 1 of whom was MVS-negative. MVS had an accuracy of 91% and performed reasonably well as a screening tool but poorly as a diagnostic tool. MVS reliability was acceptable. Children with PTS had similar quality of life as those without PTS but had higher rates of neurodevelopmental delays in gross motor skills (70% vs 24%; P = .02) and problem-solving indicators (60% vs 15%; P = .008).

CONCLUSIONS

Using the MVS scale for PTS screening in children with CHD is feasible and reliable, and the scale has good correlation with a clinical diagnosis of PTS despite a high prevalence of false-positive findings. Further research is needed to determine the clinical relevance of PTS in this population.

Clinical Impact of Chronic Venous Changes Induced by Central Lines in Children: A Cohort with Abnormal Venograms

PURPOSE

To explore the hypothesis that central venous stenosis/obstructions (CVS/O) in children are influenced by prior central venous access devices (CVADs) and are associated with future risk for thromboses.

MATERIAL AND METHODS

A convenience sample of 100 patients with abnormal venography (stenosis, collaterals, occlusions) documented during peripherally inserted central catheter (PICC) placements were identified from consecutive PICC placements (January 2008 to November 2012). The patients (41 males, 59 females, median age 2.7 years, median weight 11 kg) were categorized based on venographic presence (Group A, n = 53) or absence (Group B, n = 47) of visible connection to the superior vena cava. Each patient's CVAD history, before and after venography, was analyzed (until October 2016).

RESULTS

Before venogram, Group B patients were associated with a higher number of previous CVADs, larger diameter devices, greater incidence of malposition, and more use of polyurethane catheters than Group A patients (P < .001). An ipsilateral PICC was successfully placed in 98% of Group A, compared to 32% of Group B (P < .001). After venogram, significantly more Doppler ultrasounds (DUS) were performed and thromboses diagnosed in Group B (57% and 36%) compared to Group A (21% and 8%) (P < .003; P = .001), respectively.

CONCLUSIONS

Previous catheter characteristics influenced the severity of venographic changes of CVS/O (Group B). Group B was associated with more subsequent symptomatic thromboses. This information may assist parents and referring physicians to anticipate potential adverse sequelae from CVS/O on the child's venous health.

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

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

Efficacy of surveillance ultrasound for venous thromboembolism diagnosis in critically ill children after trauma

INTRODUCTION

Venous thromboembolism (VTE) is increasingly prevalent in injured children admitted to the intensive care unit (ICU). Few data exist to support VTE pharmacologic prophylaxis or ultrasound (US) surveillance in children with high bleeding risk. After implementation of screening US guidelines, we sought to describe our experience, hypothesizing that screening US of children at highest risk for VTE results in earlier detection and management.

STUDY DESIGN

A retrospective analysis was conducted on prospectively collected data of injured children admitted to an American College of Surgeons Verified level 1 Pediatric Trauma Center from 2010 to 2015. In patients at high risk for both VTE and bleeding (HRHR), guidelines recommended deferral of pharmacologic prophylaxis and a screening US at ≥7 ICU days if bleeding risk remained. Outcomes analyzed included VTE rates, guideline compliance, and US timing. The rate of deep vein thrombosis (DVT) detection (number of DVT captured/number of US obtained) was examined.

RESULTS

Of 4061 trauma patients, 588 (14.5%) were critically injured including 112 patients who met HRHR criteria. The rate of VTE in the HRHR group ≥7 ICU days was 25% (14/56). Of 23 VTE diagnosed in the ICU, 17 were detected by 49 US performed (34.7%), with the remaining 6 diagnosed by computed tomography. DVT was detected earlier than the US guideline recommended 7 days, independent of symptoms. Guideline compliance was 86%.

CONCLUSION

Critically injured children at risk for bleeding frequently develop VTE. Surveillance ultrasound in patients at high risk for both VTE and bleeding allows earlier detection and treatment.

LEVEL OF EVIDENCE

Therapeutic study, level II.

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

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

Phase 3, single-arm, multicenter study of dabigatran etexilate for secondary prevention of venous thromboembolism in children: Rationale and design

BACKGROUND

Anticoagulant therapy for venous thromboembolism (VTE) in children is largely based on treatment recommendations for adults. However, differences in both physiology (ie, renal maturation and drug excretion) and developmental hemostasis must be considered when treating children, as such differences could affect dose appropriateness, safety and efficacy.

OBJECTIVES

To address these concerns, a study was designed to evaluate the safety of dabigatran etexilate in children requiring secondary thrombus prevention in whom an initial VTE was associated with an identified risk factor that persisted after the acute VTE treatment period. We report herein the rationale and design of the study.

PATIENTS/METHODS

This phase 3, open-label, single-arm, multicenter, multinational, prospective cohort study will be conducted in ≥100 children aged 0 to <18 years at ~100 specialist sites worldwide. Children will be treated with dabigatran etexilate for 12 months, or for a shorter duration if their identified VTE risk factor resolves, as per current American College of Chest Physicians recommendations. A nomogram will be used to determine starting doses for each patient.

RESULTS

The primary outcomes of the study will be VTE recurrence, bleeding events, overall mortality, and VTE-related mortality. Secondary outcomes will include occurrence of post-thrombotic syndrome, the pharmacokinetics of dabigatran, and the need for dose adjustments during treatment. Data on adverse events during the study will also be collected.

CONCLUSION

This study will evaluate the safety of dabigatran etexilate for the secondary prevention of VTE in children, in addition to providing further data to guide pediatric dosing with dabigatran.

Assessment of limb edema in pediatric post-thrombotic syndrome

BACKGROUND

Pediatric tools for diagnosis of post-thrombotic syndrome (PTS) include the assessment of limb edema as a symptom (patient/proxy-reported) and as a sign. However, it is unclear whether these two approaches refer to the same clinical aspect of PTS. This could result in overestimation of disease severity. We sought to evaluate the correlation among different techniques to assess limb edema as a sign and as a symptom in children who sustained upper extremity (UE) or lower extremity (LE) deep vein thrombosis (DVT) and were, therefore, at risk of PTS.

METHODS

Limb edema was cross-sectionally measured as a symptom (ie, patient- or proxy-reported) and as a sign (ie, clinician-assessed limb circumference difference, limb volume ratio, bioimpedance spectroscopy ratio (BIS), and durometry ratio) in 140 children at risk of PTS (n = 70 UE-DVT, n = 70 LE-DVT). Item-item correlations were estimated using Pearson or Spearman correlation coefficients, as appropriate, and separately for the UE and LE groups.

RESULTS

In the UE-DVT group, proxy-reported swelling correlated weakly to moderately with circumference difference and with volume ratio, but not with BIS ratio. In the LE-DVT group, proxy-reported swelling correlated moderately with thigh circumference difference and volume ratio, and patient-reported swelling correlated moderately with BIS ratio.

CONCLUSION

Our findings suggest that patient/proxy-reported and clinician-assessed limb edema measure slightly different aspects of PTS, justifying their inclusion in pediatric PTS tools. In addition, proxy-reported swelling was in closer agreement with clinician-assessed total limb size (ie, observed edema), and patient-reported swelling in the LE seemed to reflect limb fluid content (ie, perceived edema).

A systematic review of paediatric deep venous thrombolysis

Objectives

The aim was to assess the effectiveness and safety of catheter-directed thrombolysis in children with deep venous thrombosis and to evaluate its long-term effect.

Method and results

EMBASE, Medline and Cochrane databases were searched to identify studies in which paediatric acute deep venous thrombosis patients received thrombolysis. Following title and abstract screening, seven cohort studies with a total of 183 patients were identified. Technical success was 82% and superior in regional rather than systemic thrombolysis (p < 0.00001). One cohort study identified significant difference in thrombus resolution at one year between thrombolytic and anticoagulant groups (p = 0.01). The complication rate was low, with incidence rates of major bleeding, pulmonary embolism and others at 2.8%, 1.8% and 8.4%, respectively. The overall post-thrombotic syndrome rate was 12.7%. The incidence of re-thrombosis ranged from 12.3% to 27%.

Conclusion

Thrombolysis for paediatric deep venous thrombosis is an effective and relatively safe therapeutic option, lowering the incidence of post-thrombotic syndrome and deep venous thrombosis recurrence.

The association of venous thromboembolism with survival in pediatric cancer patients: a population-based cohort study

Venous thromboembolism (VTE) is a well-recognized complication in pediatric oncology patients. Studies in adult oncology patients have suggested a potential negative association between VTE and survival, but this association has not been examined in pediatric patients yet. The aim of this study was to assess the association of VTE with survival in pediatric oncology patients. Data from all pediatric oncology patients treated at the two tertiary care centers in Atlantic Canada were pooled to create a population-based cohort. The association between VTE and survival was analyzed using a Cox proportional hazards model stratified by diagnosis group (leukemia, lymphoma, and other; sarcoma) and adjusted for age at diagnosis and sex. Out of 939 patients included in this study, 73 had a VTE (8%) and 131 (14%) patients died during the study period. Children in the leukemia/lymphoma/other group with a VTE had significantly poorer survival relative to children in the same group who did not have a VTE. Although children with sarcoma and VTE had poorer survival compared to children with sarcoma with no VTE, this association was not statistically significant. In this population-based study, we found a negative association between VTE and survival in pediatric oncology patients. If future studies confirm this association, this finding may have prognostic implications and potentially offer new avenues for the management of pediatric patients with cancer.

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.

Deep vein thrombosis in pediatric patients

Due to advances in caring for critically ill children and those with chronic diseases, rates of deep vein thrombosis (DVT) are increasing in children. Risk factors consist of central venous catheters, chronic medical conditions, thrombophilia, and various medications. Compression Doppler ultrasonography is the method most commonly used to diagnose DVT, and patients will usually present with pain and swelling of the affected limb. Anticoagulation via subcutaneous injection is the most common treatment regime for children with DVT, and the new, direct oral anticoagulants are currently under investigation. Prevention techniques are not established, but clinical studies are addressing this need.

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

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

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.

Spontaneous Subclavian Vein Thrombosis in a Healthy Adolescent Cheerleader: A Case of Paget-Schroetter Syndrome

We present the case of a healthy 13-year-old female adolescent who developed acute progressive swelling and pain in her right upper extremity that was secondary to an acute deep venous thrombosis of her right subclavian vein. Dynamic imaging revealed subclavian vein compression at the junction of the first rib and proximal third of the clavicle consistent with Paget-Schroetter syndrome, also known as effort-related thrombosis. The compressive etiology of her thrombus was most likely related to her cheerleading activity, in which she served as the pyramid base. The patient received multimodal therapy including anticoagulation, mechanical and site-directed thrombolysis, and a first rib resection. This case illustrates that frontline providers should have a high index of suspicion for an upper extremity thrombosis in pediatric patients who present with unilateral arm swelling.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Venous thromboembolism in pediatric trauma patients: Ten-year experience and long-term follow-up in a tertiary care center

BACKGROUND

Pediatric trauma patients are at high risk for development of venous thromboembolism (VTE). Our objective is to describe incidence, risk factors, and timing of development of VTE, anticoagulation complications, and long-term VTE outcomes in a critically injured pediatric population.

PROCEDURE

We did a retrospective review of pediatric (0-17 years) trauma admissions to intensive care unit from 2005 to 2014. Our center employs VTE screening and prevention protocols for high-risk patients based on hypercoagulable history, age, injuries, and medical interventions. We collected demographics, VTE prevention measures, VTE incidence, therapeutic anticoagulant use, and outcomes including postthrombotic syndrome (PTS) and clot resolution. Analysis included Wilcoxon rank-sum, Fisher exact, and logistic regression modeling.

RESULTS

Seven hundred fifty-three subjects were analyzed. No patients on chemical prophylaxis (21/753) developed VTE. Overall incidence of deep vein thrombosis (DVT) was 8.9%; pulmonary embolism (PE) was 0%. Time to diagnosis was median (interquartile range [IQR]) 10.5 (6.5-14.5) days, with 63% of clots being symptomatic. Risk factors for VTE development included severe traumatic brain injury (TBI), acute traumatic coagulopathy (defined by elevated admission international normalized ratio), age less than or equal to 3 or age 13 years or more, injury severity, and child abuse mechanism. At a median (IQR) follow-up of 13 (6-19) months, 52.1% had persistent clot and 15.8% had PTS. Therapeutic anticoagulation was not associated with clot resolution or prevention of PTS.

CONCLUSION

TBI therapy is closely linked to the development of DVT. Coagulopathy on admission is associated with hypercoagulability in the postinjury period, suggesting a patient phenotype with systemic coagulation dysregulation. Treatment was not associated with improved VTE outcomes, suggesting that pediatric protocols should emphasize VTE prevention and prophylaxis strategies.

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.

TropicALL study: Thromboprophylaxis in Children treated for Acute Lymphoblastic Leukemia with Low-molecular-weight heparin: a multicenter randomized controlled trial

Background

Venous thromboembolism (VTE) is a common and severe complication during treatment of acute lymphoblastic leukemia (ALL). An important cause is the intensive use of asparaginase. Prospective cohort studies in which prophylactic low-molecular-weight heparin (LMWH) was used to prevent VTE showed lower VTE risk than in historic control cohorts, with a negligible bleeding risk. However, the efficacy of thromboprophylaxis with LMWH during ALL treatment has never been investigated in a randomized design. Here, we present the protocol of a randomized controlled trial in which the efficacy and safety of thromboprophylaxis with high prophylactic dose LMWH versus no thromboprophylaxis will be assessed in children treated for primary ALL with asparaginase.

Methods/Design

Thromboprophylaxis in Children treated for Acute Lymphoblastic Leukemia with Low-molecular-weight heparin (TropicALL) is a multicenter, randomized controlled open-label trial conducted in the Netherlands. Patients between 1 and 19 years of age with primary ALL, who are treated within the Dutch Childhood Oncology Group (DCOG) ALL-11 or 12 study will be randomized to thromboprophylaxis with LMWH once daily, (dose of 85 IU/kg (intervention arm A)), or to no thromboprophylaxis (arm B, standard of care) during asparaginase courses of ALL treatment. Primary efficacy endpoint is symptomatic objectified VTE during ALL treatment; secondary efficacy endpoints are overall survival and the composite of symptomatic and asymptomatic objectified VTE. Primary safety endpoints are major bleeding, clinically relevant non-major bleeding and minor bleeding. A total of 324 patients will be included to obtain a relative risk reduction of 75% with a power of 80%, using a two-sided test with significance level α = 0.05.

Discussion

This trial will be the first to assess efficacy and safety of thromboprophylaxis with LMWH during asparaginase treatment for ALL in children in a randomized design.

Trail registration

Nederlands Trial Register NTR4707. Registered 30 July 2014.

Incidence and characteristics of venous thrombotic events in pediatric cancer patients: A 20-year experience in the Maritimes, Canada

OBJECTIVE

Venous thrombotic events (VTE) are a well-recognized complication in pediatric cancer patients. Population-based data on the incidence and characteristics of VTE in all pediatric cancer patients are limited. This information is crucial to identify patients at high risk and design targeted interventions accordingly. The present study was designed to determine the incidence and characteristics of VTE in the pediatric oncology population.

PARTICIPANTS

We conducted a retrospective, population-based, cohort study of patients treated in the Maritimes, Canada between 1995 and 2015.

RESULTS

There were 1210 pediatric hematology/oncology patients from the Maritimes, Canada, treated at the IWK Health Centre between 1995 and 2015. Fifty-eight (4.8%) experienced at least 1 VTE and the majority of patients experienced it within 6 months of cancer diagnosis. The median age of patients who experienced VTE was 10.7 years (SD = 6.0). The most common presenting symptom of thrombosis was central venous line dysfunction, and the most common location for thrombosis was within the upper venous system. We observed that 65.6% of the patients with VTE required >1 central venous catheters (CVC). The presence of a VTE increased the odds of requiring >1 CVC to 3.6 (95% confidence interval: 1.76-7.3).

CONCLUSION

Thus, in this large, population-based study, we present the incidence and characteristics of VTE in the pediatric oncology population and demonstrate the clinical impact of VTE in terms of loss of CVC. Larger, prospective studies are required to confirm these findings and to develop a risk model for managing and preventing VTE in this patient population.

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.

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

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

Endovascular Management of May-Thurner Syndrome in Adolescents: A Single-Center Experience

PURPOSE

To report a single-center experience in regard to the technique, safety, and clinical outcomes of endovascular therapy for treatment of May-Thurner syndrome (MTS) in adolescent patients.

MATERIALS AND METHODS

A retrospective review identified 10 patients (6 female; mean age, 16 y; range, 12-18 y; mean weight, 73 kg; range, 50-116 kg) treated by endovascular therapy for MTS from 1998 to 2015. Clinical presentations consisted of acute thrombotic MTS (n = 6) and nonthrombotic MTS (n = 4). Catheter-directed thrombolysis was performed in all cases of thrombosis. Venoplasty and stent placement were performed in all cases. Self-expanding stents 12-16 mm in diameter and 4-9 cm in length were deployed.

RESULTS

No major periprocedural complications were observed. Median follow-up was 32 months (range, 6-109 mo). Primary and secondary patency rates were 79% and 100% at 12 months and 79% and 89% at 36 months, respectively. In a single patient with permanent loss of flow in the treated segment, multiple risk factors for thrombosis were identified. Rates of posttreatment symptoms were 0% by Villalta score and 60% (n = 6; mild symptoms) by modified Villalta score at the last clinical follow-up.

CONCLUSIONS

Endovascular therapy for the treatment of MTS in our adolescent cohort was safe and effective in relieving venous obstruction. Stent placement in patients with underlying thrombophilic disorders is associated with loss of secondary patency, suggesting the need for further consideration in this population.

Postthrombotic syndrome and other outcomes of lower extremity deep vein thrombosis in children

The frequency of PTS, PE, and DVT recurrence was higher in children with Non-LR DVT than in children with LR DVT. Thrombus resolution, DVT triggering event, and sex were predictors of LE PTS in children.

Patterns of pediatric venous disease

BACKGROUND

The spectrum of chronic venous disease (CVD) is well documented in adults; clinical guidelines standardize diagnosis and treatment. There is a paucity of data published commenting on pediatric CVD exclusive of Klippel-Trénaunay syndrome (KTS) and post-thrombotic syndrome.

METHODS

This study aimed to define patterns of pediatric venous disease. All venous reflux studies performed on patients <18 years of age between January 2012 and June 2014 were reviewed. Study indication, patient history, clinical examination, and duplex ultrasound results were queried and described. Venous reflux parameters were compared using one-way analysis of variance.

RESULTS

Twenty patients were evaluated. All presented through the vascular surgery or multidisciplinary venous clinic at a tertiary academic medical center. Indications for referral included swelling (n = 10), varicose veins (n = 9), and rubor/acrocyanosis (n = 3); two patients carried a diagnosis of KTS. Mean age at study was 13 years (range, 5-17 years). Clinical examination revealed the following: dependent rubor (n = 3); edema (n = 9); and varicose veins or venous abnormality concerning for venous malformation (n = 9). There were no stigmata of chronic inflammation, hyperpigmentation, or ulceration; 90% of patients (n = 18) demonstrated venous reflux by duplex ultrasound interrogation. Mean right great saphenous vein (GSV) diameter was 0.49 cm (range, 0.31-0.66 cm); mean left GSV diameter was 0.55 cm (range, 0.24-0.93 cm). Adjunctive studies were often used (including magnetic resonance venography and lymphoscintigraphy). Despite the presence of venous reflux on imaging, an alternate diagnosis was made in 8 of 18 children (44%), including postural orthostatic hypotension syndrome (n = 2), vascular malformation (n = 2), lymphedema (n = 2), complex regional pain syndrome (n = 1), and acrocyanosis of disuse (n = 1). An additional case of KTS was identified. Three cases referred for varicose veins were diagnosed with venous malformation. Maximum GSV diameter and venous reflux time were compared across patients with isolated CVD, KTS, or an alternate diagnosis (as before). Whereas there was no significant difference in maximum GSV diameter, superficial venous reflux time was significantly increased in the patients with primary CVD and KTS (P = .0394).

CONCLUSIONS

The differential diagnosis for pediatric lower extremity edema and varicosities is broad; workup often requires adjunctive studies to secure the appropriate diagnosis. Often there is venous reflux present despite an alternative clinical diagnosis. Superficial venous reflux time may aid in the diagnosis of primary CVD. Whereas the clinical significance of pediatric venous reflux remains unclear, ongoing work to expand on venous parameters in healthy pediatric controls is warranted, as is additional follow-up to assess the natural history of pediatric venous disease.