Description of a national, multi-center registry of patients with sickle cell disease and SARS-CoV-2 infection: Data from the Pediatric COVID-19 United States Registry.

Children with sickle cell disease (SCD) are at risk of complications from viral infections, including SARS-CoV-2. We present the clinical characteristics and outcomes of pediatric patients with SCD from the Pediatric COVID-19 United States Registry who developed acute COVID-19 due to SARS-CoV-2 infection (n = 259) or multisystem inflammatory syndrome in children (MIS-C; n = 4). Nearly half of hospitalized children with SCD and SARS-CoV-2 infection required supplemental oxygen, though children with SCD had fewer intensive care (ICU) admissions compared to the general pediatric and immunocompromised populations. All registry patients with both SCD and MIS-C required ICU admission. Children with SCD are at risk of severe disease with SARS-CoV-2 infection, highlighting the importance of vaccination in this vulnerable population.

Sports participation in chronic immune thrombocytopenia: Safer than you thought?

BACKGROUND/OBJECTIVES: Pediatric patients with chronic immune thrombocytopenia (ITP) commonly have activity limitations placed to prevent injury without data guiding clinical decision-making. The objective of this study was to determine risk factors associated with injury in children with chronic ITP. DESIGN/METHODS: Retrospective single-center cohort study from January 1, 2008 to March 31, 2019 in subjects age 5-21 years with chronic ITP (platelet count < 100,000/µL for >1 year). RESULTS: One-hundred-two subjects were included, with a mean diagnosis age of 9.3 ± 4.6 years. Mean follow-up 3.8 ± 2.3 years; 61% (62) of subjects were female; 60% (61) participated in organized sports, mean 2 ± 1 sports/subject; 8.8% (9) received ITP therapy for sports participation. Common sports: basketball (28%) and soccer (28%). There were 31 injuries in 26 subjects, and 68% (21) occurred while at play. Most common injuries: 68% (21/31) soft tissue and 23% (7/31) head trauma. Fifteen (48%) injuries were severe enough for medical evaluation at the time of injury. Only one patient received acute ITP treatment for their injury. Injury was associated with participation in high-risk sports (p < .001), male sex (p = .007), and participation in multiple organized sports (p = .008). CONCLUSION: In this study of 102 pediatric subjects with chronic ITP, injury was mild and infrequent predominantly occurring while at play. The majority participated in organized sports safely. Risk of injury was associated with high-risk sport participation (p < .001). Only one injury necessitated ITP treatment, suggesting that participation in most sports is likely safe in children with chronic ITP.

The Continued Rise of Venous Thromboembolism Across US Children's Hospitals.

OBJECTIVES: In 2009, a large multicenter study demonstrated that the rate of pediatric venous thromboembolism (VTE) across US children's hospitals had significantly increased from 2001 to 2007. The objective of this study was to evaluate the rate of pediatric VTE from 2008 to 2019 using similar methodology. METHODS: A retrospective cohort study using the Pediatric Health Information System (PHIS) database. Subjects from birth to <18 years admitted from 2008 through 2019 who had an ICD-9-CM or ICD-10-CM code for VTE were included. Demographics, underling medical comorbidities and mortality were collected. VTE location and anticoagulation data during admission were extracted. RESULTS: During the 12-year study period, there were 52 401 hospital admissions among 39 713 pediatric patients with a diagnosis of VTE. The VTE admission rate increased from 46 VTE cases per 10 000 admissions in 2008 to 106 VTE cases per 10 000 admissions in 2019, a 130% increase (P < .0001) in VTE events. The median age at admission was 6.1 years, and almost one-third (31.3%) of patients with VTE were in the adolescent age group (13-17 years). Most patients (78%) had an underlying chronic medical condition. CONCLUSIONS: The rate of VTE in hospitalized pediatric patients continues to increase from a 70% increase reported from 2001 to 2007 to the 130% increase from 2008 to 2019. These findings support the need for more effective VTE prevention strategies. Clinical trials focused on risk stratification and VTE prevention are needed.

The ASH-ASPHO Choosing Wisely Campaign: 5 hematologic tests and treatments to question.

Choosing Wisely is a medical stewardship and quality-improvement initiative led by the American Board of Internal Medicine Foundation in collaboration with leading medical societies in the United States. The American Society of Hematology (ASH) has been an active participant in the Choosing Wisely project. In 2019, ASH and the American Society of Pediatric Hematology/Oncology (ASPHO) formed a joint task force to solicit, evaluate, and select items for a pediatric-focused Choosing Wisely list. By using an iterative process and an evidence-based method, the ASH-ASPHO Task Force identified 5 hematologic tests and treatments that health care providers and patients should question because they are not supported by evidence, and/or they involve risks of medical and financial costs with low likelihood of benefit. The ASH-ASPHO Choosing Wisely recommendations are as follows: (1) avoid routine preoperative hemostatic testing in an otherwise healthy child with no previous personal or family history of bleeding, (2) avoid platelet transfusion in asymptomatic children with a platelet count >10 × 103/µL unless an invasive procedure is planned, (3) avoid thrombophilia testing in children with venous access-associated thrombosis and no positive family history, (4) avoid packed red blood cells transfusion for asymptomatic children with iron deficiency anemia and no active bleeding, and (5) avoid routine administration of granulocyte colony-stimulating factor for prophylaxis of children with asymptomatic autoimmune neutropenia and no history of recurrent or severe infections. We recommend that health care providers carefully consider the anticipated risks and benefits of these identified tests and treatments before performing them.

The ASH-ASPHO Choosing Wisely Campaign: 5 hematologic tests and treatments to question.

Choosing Wisely is a medical stewardship and quality-improvement initiative led by the American Board of Internal Medicine Foundation in collaboration with leading medical societies in the United States. The American Society of Hematology (ASH) has been an active participant in the Choosing Wisely project. In 2019, ASH and the American Society of Pediatric Hematology/Oncology (ASPHO) formed a joint task force to solicit, evaluate, and select items for a pediatric-focused Choosing Wisely list. By using an iterative process and an evidence-based method, the ASH-ASPHO Task Force identified 5 hematologic tests and treatments that health care providers and patients should question because they are not supported by evidence, and/or they involve risks of medical and financial costs with low likelihood of benefit. The ASH-ASPHO Choosing Wisely recommendations are as follows: (1) avoid routine preoperative hemostatic testing in an otherwise healthy child with no previous personal or family history of bleeding, (2) avoid platelet transfusion in asymptomatic children with a platelet count 10 × 103 /µL unless an invasive procedure is planned, (3) avoid thrombophilia testing in children with venous access-associated thrombosis and no positive family history, (4) avoid packed red blood cells transfusion for asymptomatic children with iron deficiency anemia and no active bleeding, and (5) avoid routine administration of granulocyte colony-stimulating factor for prophylaxis of children with asymptomatic autoimmune neutropenia and no history of recurrent or severe infections. We recommend that health care providers carefully consider the anticipated risks and benefits of these identified tests and treatments before performing them.

Utilization of an Electronic Medical Record-integrated Dashboard Improves Identification and Treatment of Anemia and Iron Deficiency in Pediatric Inflammatory Bowel Disease.

BACKGROUND: Iron deficiency (ID) and anemia are one of the most common extraintestinal manifestations of inflammatory bowel disease (IBD), usually complicating the course both in ulcerative colitis and Crohn's disease. Despite their high prevalence and significant impact on patients, this particular aspect is still underestimated by clinicians. Although guidelines have been recently published to address this problem, these recommendations do not address pediatric specific concerns and do not provide guidance as to how implement these guidelines in clinical practice. The aims of this quality improvement (QI) initiative were to improve the rates of detection and treatment of anemia in children with IBD. METHODS: After the creation of a multidisciplinary team of skateholders in IBD and anemia, we launched a multifaceted QI strategy that included the development of a pediatric evidence-based care pathway, utilization of an electronic medical record (EMR)-integrated dashboard to track patients, and generation of an automated provider-based monthly report. Data were collected and graphed into statistical process control charts. RESULTS: These key strategies resulted in improved rates of ID screening from 31.7% to 63.6%, in increased treatment rates from 38.2% to 49.9%, and in decreased prevalence of anemia from 35.8% to 29.7%, which was reflected by a greater decline in patients with quiescent disease. CONCLUSIONS: Quality improvement strategies incorporating the creation of a pediatric evidence-based care pathway with an EMR-supported electronic dashboard were the foundation of a successful intervention in the management of ID and anemia in pediatric IBD. Our positive results demonstrate the potential of QI initiatives using automated technology to assist clinicians in their commitment to provide evidence-based IBD care and enhance patient outcomes.

The impact of extended half-life factor concentrates on prophylaxis for severe hemophilia in the United States.

With licensure of extended half-life (EHL) factor products and the changing landscape of available hemophilia products, patients and providers have options for less treatment-intense prophylaxis. The impact of these products in clinical practice to date remains understudied. We aimed to quantify the use of EHL products in prophylaxis in the US using the ATHN-dataset, a database of 145 ATHN-affiliated hemophilia treatment centers (HTCs). Further, we aimed to quantify the impact of EHL on key hemophilia indicators including annualized bleed rates (ABRs), hemophilia joint health scores (HJHS) and quality of life (QOL) metrics. The use of EHL vs standard half-life (SHL) products in severe hemophilia was compared between June 2018 and March 2019 using the ATHN-dataset. A cohort of patients was also recruited from seven participating HTCs in order to compare ABR, HJHS and QOL between product classes. By March 2019 the number of individuals with severe Hemophilia A (SHA) receiving EHLs remained relatively stable (28.4%), whereas the number of prescribed non-factor products increased to 7.1%, with a diminishing majority of patients (64.0%) continuing to receive SHLs. The majority of patients with severe hemophilia B (SHB) received treatment with EHLs including 57.5% by March 2019. There was a trend toward lower ABR with use of EHLs in SHA and SHB, although this did not result in improved HJHS nor QOL. EHL use in the United States in severe hemophilia continues to increase, although at a slower rate in SHA with the availability of non-factor therapy. The impact of the EHL therapies in clinical practice should continue to be examined prospectively.

Utility of repeat testing in the evaluation for von Willebrand disease in pediatric patients.

BACKGROUND: Von Willebrand disease (VWD) is the most common inherited bleeding disorder and is caused by quantitative and qualitative defects in von Willebrand factor (VWF). The laboratory diagnosis of VWD in pediatric patients is complicated by VWF interassay and intra-assay variability, stress-induced elevations in VWF levels, and a lack of significant bleeding history with which to correlate test results. OBJECTIVE: Guidelines recommend repeat testing in patients with a high suspicion of VWD and unclear laboratory assay results; however, no studies have evaluated the utility of repeat VWF testing in pediatric patients. METHODS: This retrospective single-center cohort study aimed to determine clinical variables associated with requiring more than one test to diagnose VWD and to establish a cutoff VWF value above which further testing is not informative. RESULTS: Of 811 patients evaluated for a suspected bleeding disorder, 22.2% were diagnosed with VWD, with ~70% diagnosed on the first test. Patients with VWD were younger (5.8 vs. 8.5 years, P = .002) and more likely to have a family history of VWD (38% vs. 22%, P < .001) than those without VWD. Univariate analysis failed to identify any clinical variables that correlated with needing multiple tests for a VWD diagnosis. A cutoff of 100 IU/dL for VWF antigen or activity on the first test yielded negative predictive values >95%. CONCLUSIONS: We demonstrate that the majority of pediatric patients had diagnostic VWF values on the first set of testing. Pediatric patients without a family history of VWD and VWF levels >100 IU/dL may not need further testing to rule out the diagnosis of VWD.

Primary thromboprophylaxis in hospitalized children: A multi-center retrospective analysis.

BACKGROUND/OBJECTIVES: Hospital acquired venous thromboembolism in children is associated with significant morbidity/mortality. Prevention strategies include sequential compression devices and prophylactic anticoagulation but these interventions carry risk and are poorly studied in children. Objectives were to evaluate primary thromboprophylaxis use in hospitalized children over time and the associated bleeding risk. MATERIALS AND METHODS: Retrospective study of hospitalized patients aged 10-18 years within the Pediatric Health Information System administrative database from January 2008-September 2015. Factors associated with thromboprophylaxis receipt and bleeding were identified using generalized linear mixed effects models. RESULTS: Of 1,075,383 hospitalizations, 10,544 (1%) received prophylactic enoxaparin and 58,768 (5%) received mechanical compression. Mechanical thromboprophylaxis increased slightly over time (4.3% in 2008, 6.2% in 2015), enoxaparin use did not (0.8% in 2008, 1.2% in 2015). Patients aged 16-18 were more likely than younger children (10-12) to receive pharmacologic (adjusted odds ratio [aOR] 3.1, 95% confidence interval [CI] 2.9-3.3) or mechanical thromboprophylaxis (aOR 2.9, 95% CI 2.9-3). Patients on rehabilitation medical service were more likely to receive prophylactic enoxaparin (aOR 53, 95% CI 44.1-64.5). 5.6% (589/10,544) of patients receiving enoxaparin prophylaxis had bleeding. Thromboprophylaxis use by hospital varied with a range of 0.25-3.3% for enoxaparin and 2-26.2% for mechanical compression. CONCLUSION: Thromboprophylaxis is infrequently utilized in hospitalized children. Pharmacologic prophylaxis with enoxaparin remains low and has not substantially increased over time. Significant variability exists across hospitals and services in the administration of both mechanical and pharmacologic thromboprophylaxis highlighting the need for further evidence to standardize practice.

How I approach managing student athletes at risk for bleeding.

Frequently, pediatric hematologists need to provide guidance regarding sports participation for children with congenital coagulopathies, immune thrombocytopenia, and those receiving anticoagulation. Although sports participation has clear health and psychosocial benefits, it can be associated with harm secondary to bleeding from injury. Decision-making for sports involvement should be individualized, patient centered, and well informed. This review focuses on the current data regarding the benefit as well as risks for sports participation and provides a framework for advising and supporting the student athlete who is at risk for bleeding.

Utility of the immature platelet fraction in pediatric immune thrombocytopenia: Differentiating from bone marrow failure and predicting bleeding risk.

BACKGROUND: Differentiating childhood immune thrombocytopenia (ITP) from other cause of thrombocytopenia remains a diagnosis of exclusion. Additionally factors that predict bleeding risk for those patients with ITP are currently not well understood. Previous small studies have suggested that immature platelet fraction (IPF) may differentiate ITP from other causes of thrombocytopenia and in combination with other factors may predict bleeding risk. METHODS: We performed a retrospective chart review of thrombocytopenic patients with an IPF measured between November 1, 2013 and July 1, 2015. Patients were between 2 months and 21 years of age with a platelet count <50 × 109 /l. Each patient chart was reviewed for final diagnosis and bleeding symptoms. A bleeding severity score was retrospectively assigned. RESULTS: Two hundred seventy two patients met inclusion criteria, 97 with ITP, 11 with bone marrow failure (BMF), 126 with malignancy, and 38 with other causes of thrombocytopenia. An IPF > 5.2% differentiated ITP from BMF with 93% sensitivity and 91% specificity. Absolute immature platelet number (AIPN) was significantly lower in ITP patients with severe to life-threatening hemorrhage than those without, despite similar platelet counts. On multivariate analysis, an IPF < 10.4% was confirmed as an independent predictor of bleeding risk at platelet counts <10 × 109 /l in patients with ITP. CONCLUSIONS: IPF measurement alone has utility in both the diagnosis of ITP and identifying patients at increased risk of hemorrhage. Further study is required to understand the pathophysiological differences of ITP patients with lower IPF/AIPN.

Pediatric Hospital Acquired Venous Thromboembolism.

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

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.

A survey of pediatric hematology/oncology specialists regarding management of central line associated venous thrombosis.

Central venous catheters (CVCs) account for the largest proportion of thrombotic events in pediatric patients. Questions remain regarding adequate treatment and prevention methods. We surveyed pediatric hematology/oncology specialists, using hypothetical cases to assess management strategies for acute CVC thrombosis and secondary prevention. Survey respondents varied in the use of the thrombophilia evaluation (33.3%, 41/123) and duration of treatment (6 weeks: 54.1%, 66/122). Secondary CVC prophylaxis was utilized by 36.6% (45/123) of respondents and by 24.4% (30/123) but only if there was a documented thrombophilia. This heterogeneity highlights the need for clinical studies to address these important clinical questions.

Antithrombin Concentrate Use in Pediatric Extracorporeal Membrane Oxygenation: A Multicenter Cohort Study.

OBJECTIVE: To describe antithrombin concentrate use and to compare thrombotic and hemorrhagic outcomes throughout the hospital stay in pediatric subjects who received extracorporeal membrane oxygenation in a Pediatric Health Information System-participating children's hospital. DESIGN: Retrospective, multi-center, cohort study. SETTING: Forty-three free-standing children's hospitals participating in Pediatric Health Information System. SUBJECTS: Children older than or equal to 18 years of age who underwent extracorporeal membrane oxygenation between 2003 and 2012. INTERVENTIONS: Subjects were classified as receiving antithrombin if they received at least one dose of antithrombin while on extracorporeal membrane oxygenation. MEASUREMENTS AND MAIN RESULTS: International Classification of Diseases, Ninth Revision, Clinical Modification codes codes were used to identify hemorrhagic and thrombotic complications during their hospitalization. Pediatric Health Information System data were analyzed to determine hospital-length of stay and in-hospital mortality. A total of 1,931 of 8,601 eligible subjects (21.5%) received at least one dose of antithrombin during their extracorporeal membrane oxygenation course. Antithrombin use during extracorporeal membrane oxygenation increased from 2.4% to 51.9% (p < 0.001) over the 10-year study period. Subjects who received antithrombin while on extracorporeal membrane oxygenation were younger (p = 0.02), had more chronic conditions (p < 0.001), and longer hospital stays (p < 0.001). On multivariate analysis, antithrombin use was associated with thrombotic events (odds ratio, 1.55; 95% CI, 1.36-1.77; p < 0.001), hemorrhagic events (odds ratio, 1.27; 95% CI, 1.14-1.42; p < 0.001), and longer hospital length of stays (slope coefficient, 1.05 d; 95% CI, 1.04-1.06; p < 0.001). No difference was observed in mortality (odds ratio, 0.99; 95% CI, 0.89-1.11; p = 0.90). CONCLUSIONS: In this multicenter retrospective cohort study, subjects who received antithrombin during extracorporeal membrane oxygenation had a higher number of thrombotic and hemorrhagic events throughout the hospitalization and longer length of stays without an associated difference in mortality. While limitations exist with this analysis and results should be interpreted with caution, the fact remains that over half of pediatric patients on extracorporeal membrane oxygenation are currently receiving antithrombin without clear benefit, with extra cost, and potential harms, there needs to be strong consideration for a clinical trial.

Multicenter Cohort Study Comparing U.S. Management of Inpatient Pediatric Immune Thrombocytopenia to Current Treatment Guidelines.

BACKGROUND: Recent pediatric immune thrombocytopenia (ITP) guidelines have significantly altered and are encouraging an observational approach for patients without significant bleeding regardless of their platelet count. PROCEDURE: This retrospective multicenter cohort study utilized the Pediatric Health Information Systems (PHIS) administrative database. Subjects were 6 months to 18 years of age, admitted to a PHIS hospital between January 1, 2008 and September 30, 2014, with a primary diagnosis code for ITP. International Classification of Disease, Ninth Revision, Clinical Modification Code (ICD-9-CM) discharge codes identified significant bleeding. Pharmaceutical billing codes identified the use of pharmacologic therapy for ITP. Clinical management during preguideline admissions (January 1, 2008 to August 31, 2011) was compared to postguideline admissions (September 1, 2011 to September 30, 2014). RESULTS: A total of 4,937 subjects met inclusion criteria with a mean age of 6.2 (SD 5) years; 93.4% (4,613/4,937) received pharmacologic treatment for ITP but only 14.2% (699/4,937) had ICD-9-CM codes for significant bleeding; 11.5% (570/4,937) of subjects were readmitted. In comparing pre- versus postguideline time periods, the proportion of subjects receiving ITP pharmacologic treatment did not change (92.9% vs. 94.1%; P = 0.26). A decrease was found in the proportion of bone marrows performed (9.7% vs. 6.4%; P < 0.001) and length of stay (2.3 vs. 2 days; P < 0.001). The proportion of ITP admissions from 2012 to 2014 was modestly decreased when compared to 2008-2010 (12.9 vs. 14.5/10,000 PHIS admissions, P < 0.001). CONCLUSIONS: Despite guidelines and evidence that supports a watchful waiting approach for pediatric patients with ITP, a large proportion of inpatients without significant bleeding are still receiving pharmacologic therapy. Continued efforts are needed to address why inpatient U.S. practice patterns are so discrepant from current treatment guidelines.

Validation Study of the Composite Score to Identify Von Willebrand Disease in Children.

BACKGROUND: The diagnosis of type 1 von Willebrand disease (VWD) presents a diagnostic challenge in children. In fact, 25% or more of children with VWD may be diagnosed only after they experience postoperative bleeding. We previously described a 4-variable composite score that has 92.5% sensitivity and 95% specificity for diagnosing VWD in children with known VWD when 2 of 4 criteria are positive: (1) Tosetto bleeding score ≥ 1; (2) family history of VWD; (3) personal history of iron deficiency anemia; and/or (4) positive James early bleeding score. The purpose of this study was to prospectively validate a composite score of ≥ 2 for identifying children with VWD. PROCEDURE: Children without a previously diagnosed bleeding disorder presenting for hematology evaluation were enrolled. Sensitivity, specificity, positive, and negative predictive value of the composite score was determined. RESULTS: A total of 193 subjects were enrolled from 12 participating centers were included in the analysis. Forty-seven children had type 1 VWD, including 11 with von Willebrand Ristocetin Cofactor (VWF):RCo < 30 IU/dL, 14 subjects with a VWF:RCo 30 to 39 IU/dL, and 22 with a VWF:RCo 40 to 49 IU/dL. Including all 4 variables, a composite score of ≥ 2 had a sensitivity of 63.6% to 76.0%, specificity of 33.5% to 35.1%, negative predictive value of 76.9% to 93.8%, and positive predictive value of 5.5% to 25%. CONCLUSIONS: The negative predictive value of the composite score was robust, especially at lower VWF:RCo suggesting that VWD testing could be eliminated in nearly a third of children referred for VWD testing.

Thrombotic events in critically ill children with myocarditis.

BACKGROUND: Children with myocarditis have multiple risk factors for thrombotic events, yet the role of antithrombotic therapy is unclear in this population. We hypothesised that thrombotic events in critically ill children with myocarditis are common and that children with myocarditis are at higher risk for thrombotic events than children with non-inflammatory dilated cardiomyopathy. METHODS: This is a retrospective chart review of all children presenting to a single centre cardiac intensive care unit with myocarditis from 1995 to 2008. A comparison group of children with dilated cardiomyopathy was also examined. Antithrombotic regimens were recorded. The primary outcome of thrombotic events included intracardiac clots and any thromboembolic events. RESULTS: Out of 45 cases with myocarditis, 40% were biopsy-proven, 24% viral polymerase chain reaction-supported, and 36% diagnosed based on high clinical suspicion. There were two (4.4%) thrombotic events in the myocarditis group and three (6.7%) in the dilated cardiomyopathy group (p = 1.0). Neither the use of any antiplatelet or anticoagulation therapy, use of intravenous immune globulin, presence of any arrhythmia, nor need for mechanical circulatory support were predictive of thrombotic events in the myocarditis, dilated cardiomyopathy, or combined groups. CONCLUSIONS: Thrombotic events in critically ill children with myocarditis and dilated cardiomyopathy occurred in 6% of the combined cohort. There was no difference in thrombotic events between inflammatory and non-inflammatory cardiomyopathy groups, suggesting that the decision to use antithrombotic prophylaxis should be based on factors other than the underlying aetiology of a child's acute decompensated heart failure.