Efficacy and safety of antithrombin supplementation in neonates and infants on a continuous heparin infusion.

Background: Antithrombin (AT) is a natural anticoagulant and potent inhibitor of several coagulation proteins, including activated factor X (FXa) and FIIa. The therapeutic activity of heparin depends on the presence of AT. Levels of plasma AT are low in neonates and young infants compared to those in adults. Exogenous AT supplementation is postulated to enhance the activity of heparin and facilitate attainment of therapeutic anticoagulation in infants. Objectives: To describe the efficacy and safety of AT administration in infants on a continuous heparin infusion. Methods: Retrospective cohort study of 50 infants who received AT while on a heparin infusion. The primary efficacy outcome was attainment of therapeutic anticoagulation within 48 hours after AT administration. Secondary outcomes included the percent of partial thromboplastin time (PTT) levels and/or antifactor Xa (anti-FXa) activity within the therapeutic window, attainment of the target AT activity level, the incidence and severity of bleeding, and all-cause in-hospital mortality. A secondary analysis investigated the relationship between simultaneously measured PTT levels and anti-FXa activity used for heparin monitoring. Results: AT supplementation resulted in achievement of at least one therapeutic PTT level or anti-FXa activity in 90% of AT courses, though not sustained. PTT was within the therapeutic window more often than anti-FXa activity. When measured simultaneously, therapeutic anti-FXa levels were associated with supratherapeutic PTT levels. Conclusion: AT supplementation in infants on a continuous heparin infusion may transiently improve the therapeutic effect of heparin, but this is largely dependent on the laboratory parameters used for monitoring.

Improving Anticoagulation Care for Pediatric Oncology Patients: A Quality Improvement Initiative.

Background: Cancer is associated with increased venous thromboembolism in children. Risk factors for venous thromboembolism in this cohort include using central venous catheters, mass effect from underlying malignancy, chemotherapy, and surgery. Anticoagulation management in this cohort is challenging, given recurrent episodes of thrombocytopenia, the need for invasive procedures, and coagulopathy. A quality improvement (QI) initiative was developed to improve hematology consultation services and provide documentation of an individualized anticoagulation care plan for this high-risk cohort. Methods: Through the use of QI methods, interviews of stakeholders, expert consensus, and review of baseline data, a multidisciplinary team was organized, and key drivers relevant to improving access to hematology consultations and documentation of individualized anticoagulation care plans were identified. We used a Plan-Do-Study-Act model to improve hematology consultations and documentation of anticoagulation care plan (process measure). Outcome measures were bleeding and thrombosis recurrence/progression. Results: Seventeen patients with oncologic and venous thromboembolism diagnoses were included as baseline data. Slightly over half of these patients [53% (n = 9)] had a hematology consultation, and 7 (43.8%) had documentation of an anticoagulation care plan. After implementing QI methods, all 34 patients (100%) received hematology consultations and documentation of an anticoagulation care plan, and this measure was sustained for 1 year. Bleeding and thrombosis rates were similar in the baseline and post-QI cohorts. Conclusions: QI interventions proved effective in sustaining access to hematology consultations and providing anticoagulation care plans for patients with concomitant improved anticoagulation plan documentation for patients.

Clinical decision support to enhance venous thromboembolism pharmacoprophylaxis prescribing for pediatric inpatients with COVID-19.

OBJECTIVE: To design and evaluate a clinical decision support (CDS) module to improve guideline concordant venous thromboembolism (VTE) pharmacoprophylaxis prescribing for pediatric inpatients with COVID-19. MATERIALS AND METHODS: The proportion of patients who met our institutional clinical practice guideline's (CPG) criteria for VTE prophylaxis was compared to those who triggered a CDS alert, indicating the patient needed VTE prophylaxis, and to those who were prescribed prophylaxis pre and post the launch of a new VTE CDS module to support VTE pharmacoprophylaxis prescribing. The sensitivity, specificity, positive predictive value (PPV), negative predictive value, F1-score and accuracy of the tool were calculated for the pre- and post-intervention periods using the CPG recommendation as the gold standard. Accuracy was defined as the sum of the true positives and true negatives over the sum of the true positives, false positives, true negatives, and false negatives. Logistic regression was used to identify variables associated with correct thromboprophylaxis prescribing. RESULTS: A significant increase in the proportion of patients triggering a CDS alert occurred in the post-intervention period (44.3% vs. 6.9%, p < .001); however, no reciprocal increase in VTE prophylaxis prescribing was achieved (36.6% vs. 40.9%, p = .53). The updated CDS module had an improved sensitivity (55.0% vs. 13.3%), NPV (44.9% vs. 36.3%), F1-score (66.7% vs. 23.5%), and accuracy (62.5% vs. 42.0%), but an inferior specificity (78.6% vs. 100%) and PPV (84.6% vs. 100%). DISCUSSION: The updated CDS model had an improved accuracy and overall performance in correctly identifying patients requiring VTE prophylaxis. Despite an increase in correct patient identification by the CDS module, the proportion of patients receiving appropriate pharmacologic prophylaxis did not change. CONCLUSION: CDS tools to support correct VTE prophylaxis prescribing need ongoing refinement and validation to maximize clinical utility.

Thrombotic complications in children with Coronavirus disease 2019 and Multisystem Inflammatory Syndrome of Childhood.

Coronavirus disease 2019 (COVID-19) associated coagulopathy is multifactorial and involves inflammation driven hypercoagulability, endothelial dysfunction, platelet activation, and impaired fibrinolysis. Hospitalized adults with COVID-19 are at an increased risk of both venous thromboembolism and ischemic stroke, resulting in adverse outcomes, including increased mortality. Although COVID-19 in children follows a less severe course, both arterial and venous thromboses have been reported in hospitalized children with COVID-19. Additionally, some children develop a postinfectious, hyperinflammatory illness termed multisystem inflammatory syndrome of childhood (MIS-C), which is also associated with hypercoagulability and thrombosis. Several randomized trials have evaluated the safety and efficacy of antithrombotic therapy in adults with COVID-19, although similar pediatric data are lacking. In this narrative review, we discuss the postulated pathophysiology of COVID-19 coagulopathy and summarize principal findings of the recently completed adult trials of antithrombotic therapy. We provide an up-to-date summary of pediatric studies investigating the rate of venous thromboembolism and ischemic stroke in COVID-19 and multisystem inflammatory syndrome of childhood in addition to reviewing the findings of the single, nonrandomized pediatric trial investigating the safety of prophylactic anticoagulation. Lastly, we outline adult and pediatric consensus guidelines on the use of antithrombotic therapy in this cohort. A detailed discussion of the practical implementation and current limitations of published data will hopefully address the knowledge deficits surrounding the use of antithrombotic therapy in children with COVID-19 and generate hypotheses for future research.

Impact of SERPINC1 mutation on thrombotic phenotype in children with congenital antithrombin deficiency-first analysis of the International Society on Thrombosis and Haemostasis pediatric antithrombin deficiency database and biorepository.

BACKGROUND: The natural history and genotype-phenotype correlation of congenital antithrombin (AT) deficiency in children are unknown. OBJECTIVES: To describe the clinical presentation of congenital AT deficiency in children and evaluate its correlation to specific mutations in SERPINC1. METHODS: In 2017, a prospective pediatric database and DNA biorepository for congenital AT deficiency was established. During the pilot phase, the database was opened at 4 tertiary care centers in Canada and US. Approval from research ethics board was obtained at each participating center. Written consent/assent was obtained from guardians/subjects who met eligibility. Demographic/clinical data were uploaded into a database. DNA extraction and SERPINC1 sequencing were centralized for US centers. Standard statistical methods were used to summarize parameters. Probability of VTE-free survival was assessed using the Kaplan-Meier method. RESULTS: Overall, 43 participants (25 females) from 31 unique kindreds were enrolled. Median age (range) at enrollment was 14.8 years (1-21 years). Median AT activity was 52% (24%-87%), and median AT antigen (n = 20) was 55% (38%-110%). Nineteen (44%) participants had a history of venous thromboembolism (VTE). Median age at VTE diagnosis was 12.8 years (0.1-19.2 years). SERPINC1 sequencing was completed for 31 participants and 21 unique mutations were identified, including 5 novel variants. Probability of 5-year VTE-free survival (95% CI) for carriers of missense mutations (92.0% [95% CI: 71.6%-97.9%]) was significantly higher compared with carriers of null mutations (66.7% [95% CI: 19.5%-90.4%]); p = .0012. CONCLUSION: To our knowledge, this is the first pediatric study to document a severe thrombotic phenotype in carriers of null mutations in SERPINC1, when compared with carriers of missense mutations; underscoring the importance of genetic testing.

Improving guideline-concordant thromboprophylaxis prescribing for children admitted to hospital with COVID-19.

BACKGROUND: The incidence of venous thrombo-embolism (VTE) in hospitalized children has increased by 130%-200% over the last two decades. Given this increase, many centers utilize electronic clinical decision support (CDS) to prognosticate VTE risk and recommend prophylaxis. SARS-CoV-2 infection (COVID-19) is a risk factor for VTE; however, CDS developed before the COVID-19 pandemic may not accurately prognosticate VTE risk in children with COVID-19. This study's objective was to identify areas to improve thromboprophylaxis recommendations for children with COVID-19. METHODS: Inpatients with a positive COVID-19 test at admission were identified at a quaternary-care pediatric center between March 1, 2020 and January 20, 2022. The results of the institution's automated CDS thromboprophylaxis recommendations were compared to institutional COVID-19 thromboprophylaxis guidelines and to the actual thromboprophylaxis received. CDS optimization was performed to improve adherence to COVID-19 thromboprophylaxis recommendations. RESULTS: Of the 329 patients included in this study, 106 (28.2%) were prescribed pharmaco-prophylaxis, 167 (50.8%) were identified by the institutional COVID-19 guidelines as requiring pharmaco-prophylaxis, and 45 (13.2%) were identified by the CDS as needing pharmaco-prophylaxis. On univariate analysis, only age 12 years or more was associated with recipient of appropriate prophylaxis (OR 1.78, 95% CI: 1.13-2.82, p = .013). Five patients developed VTEs; three had symptoms at presentation, two were identified as high risk for VTE by both the automated and best practice assessments but were not prescribed pharmaco-prophylaxis. CONCLUSION: Automated thromboprophylaxis recommendations developed prior to the COVID-19 pandemic may not identify all COVID-19 patients needing pharmaco-prophylaxis. Existing CDS tools need to be updated to reflect COVID-19-specific risk factors for VTEs.

High Rate of Venous Thromboembolism in Severe Pediatric Intestinal Failure.

OBJECTIVE: To quantify the rate of venous thromboembolism (VTE) in patients with pediatric intestinal failure and identify associated risk factors. STUDY DESIGN: We performed a retrospective cohort study in pediatric patients (<21 years old) with severe pediatric intestinal failure (≥90 consecutive days of parenteral nutrition) secondary to short bowel syndrome who were treated from 2014 to 2021 at an interdisciplinary intestinal rehabilitation program. The primary outcome was the incidence of VTE. Multivariable regression was performed to identify independent clinical predictors of VTE. RESULTS: A total of 263 patients (59.7% male) met the criteria for inclusion. The cumulative incidence of VTE was 28.1%, with a rate of 0.32 VTEs per 1000 catheter-days. On univariate analysis, the number of catheter days, number of catheters, and history of central line-associated blood stream infection were associated with VTE. On multivariable logistic regression, a higher number of catheters was an independent risk factor for VTE (aOR, 1.17; 95% CI, 1.06-1.29). Additionally, earlier gestational age was a risk factor for VTE such that every week decrease in gestational age conferred a 9% increased risk of VTE (aOR, 1.09; 95% CI, 1.02-1.16). CONCLUSIONS: In this retrospective study, 28.1% of patients with severe pediatric intestinal failure developed VTE; the number of catheters and early gestational age were noted to be independent risk factors for VTE. This high incidence of VTE highlights the need to investigate VTE in pediatric intestinal failure prospectively, including the potential benefit of prophylactic anticoagulation.

Hemostatic and Thrombotic Considerations in the Diagnosis and Management of Childhood Arterial Ischemic Stroke: A Narrative Review.

Although rare in children, arterial ischemic stroke (AIS) is associated with increased mortality and neurological morbidity. The incidence of AIS after the neonatal period is approximately 1-2/100,000/year, with an estimated mortality of 3-7%. A significant proportion of children surviving AIS experience life-long neurological deficits including hemiparesis, epilepsy, and cognitive delays. The low incidence of childhood AIS coupled with atypical clinical-presentation and lack of awareness contribute to delay in diagnosis and consequently, the early initiation of treatment. While randomized-clinical trials have demonstrated the efficacy and safety of reperfusion therapies including thrombolysis and endovascular thrombectomy in appropriately-selected adult patients, similar data for children are unavailable. Consequently, clinical decisions surrounding reperfusion therapy in childhood AIS are either extrapolated from adult data or based on local experience. The etiology of childhood AIS is multifactorial, often occurring in the setting of both acquired and congenital risk-factors including thrombophilia. While multiple studies have investigated the association of thrombophilia with incident childhood AIS, its impact on stroke recurrence and therefore duration and intensity of antithrombotic therapy is less clear. Despite these limitations, a significant progress has been made over the last decade in the management of childhood AIS. This progress can be attributed to international consortiums, and in selected cohorts to federally-funded clinical trials. In this narrative review, the authors have systematically appraised the literature and summarize the hemostatic and thrombotic considerations in the diagnosis and management of childhood AIS focusing on the evidence supporting reperfusion therapies, relevance of thrombophilia testing, and duration and drug choices for secondary-prophylaxis.

Illustrated State-of-the-Art Capsules of the ISTH 2022 Congress.

The ISTH London 2022 Congress is the first held (mostly) face-to-face again since the COVID-19 pandemic took the world by surprise in 2020. For 2 years we met virtually, but this year's in-person format will allow the ever-so-important and quintessential creativity and networking to flow again. What a pleasure and joy to be able to see everyone! Importantly, all conference proceedings are also streamed (and available recorded) online for those unable to travel on this occasion. This ensures no one misses out. The 2022 scientific program highlights new developments in hemophilia and its treatment, acquired and other inherited bleeding disorders, thromboinflammation, platelets and coagulation, clot structure and composition, fibrinolysis, vascular biology, venous thromboembolism, women's health, arterial thrombosis, pediatrics, COVID-related thrombosis, vaccine-induced thrombocytopenia with thrombosis, and omics and diagnostics. These areas are elegantly reviewed in this Illustrated Review article. The Illustrated Review is a highlight of the ISTH Congress. The format lends itself very well to explaining the science, and the collection of beautiful graphical summaries of recent developments in the field are stunning and self-explanatory. This clever and effective way to communicate research is revolutionary and different from traditional formats. We hope you enjoy this article and will be inspired by its content to generate new research ideas.

Moderate-intensity aerobic exercise vs desmopressin in adolescent males with mild hemophilia A: a randomized trial.

Persons with mild hemophilia A (HA) may use intranasal desmopressin prior to sports participation. Desmopressin is expensive and can cause vomiting, headache, palpitation, and occasionally seizures. Our group has previously documented a 2.3-fold increase in factor VIII activity (FVIII:C) in adolescents with mild HA after moderate-intensity aerobic exercise. Herein, we report principal findings of a randomized trial of intranasal desmopressin vs a standardized, moderate-intensity aerobic exercise regimen in adolescents with mild HA. Our primary objective was to compare the change in FVIII:C associated with these 2 interventions. We also examined changes in hemostatic parameters arising from their sequential administration. The study was conducted simultaneously at the Hospital for Sick Children, Canada, and Nationwide Children's Hospital, USA. Thirty-two eligible male adolescents (mean age ± standard deviation: 16.1 ± 2.6 years) with mild HA (mean baseline FVIII:C: 27.9% ± 18.4%) were randomized to 1 of 4 study arms (desmopressin followed by exercise, desmopressin alone, exercise followed by desmopressin, and exercise alone). Blood work was obtained at baseline and at 3 subsequent time-points. Participants randomized to exercise cycled on an ergometer for approximately 12 minutes, with the final 3 minutes at 85% of their predicted maximum heart rate. Standard weight-based dosing of desmopressin was used. Mean immediate increase in FVIII:C was 1.7-fold with exercise compared with 1.9-fold with desmopressin (noninferiority, P = .04). Exercise-induced improvement in hemostatic parameters including FVIII:C was brief compared with more sustained improvements seen with desmopressin. More than 60% of participants randomized to receive both exercise and desmopressin achieved normal (>50%) FVIII:C, 75 and 135 minutes into the study protocol.

Appendix to the Society of Interventional Radiology Consensus Guidelines for the Periprocedural Management of Thrombotic and Bleeding Risk in Patients Undergoing Percutaneous Image-Guided Interventions: Pediatric Considerations.

PURPOSE: To provide guidance on the use of anticoagulant and antithrombotic agents in pediatric patients undergoing interventional radiology procedures. MATERIALS AND METHODS: A multidisciplinary writing group conducted a comprehensive literature search to identify studies on the topic of interest. Recommendations were developed for procedural risk and medication dosage and withholding. A modified Delphi technique was used to achieve consensus agreement on the recommendations. RESULTS: A total of 24 studies, including systematic reviews and meta-analyses, randomized controlled trials, and prospective and retrospective cohort studies, were identified as relevant. The expert writing group agreed on procedural risk categorization, laboratory testing thresholds, and medication dosage and withholding recommendations specific to pediatric practice. They additionally described the nuances of anticoagulation in clinical conditions specific to pediatrics. CONCLUSIONS: The Society of Interventional Radiology recommends following the guidance provided in the document when developing multidisciplinary management protocols for anticoagulation and antithrombotic treatment in pediatric patients undergoing interventional radiology procedures.

Venous thromboembolism in pediatric patients with sickle cell disease: A north American survey on experience and management approaches of pediatric hematologists.

BACKGROUND: There is a lack of pediatric-specific data to guide recommendations for prevention and management of venous thromboembolism (VTE) in sickle cell disease (SCD). Experience and expert opinion in this area have not been reported. OBJECTIVES: To characterize the management practices of pediatric hematologists in SCD-associated VTE. We hypothesized there is substantial variability in duration of therapy and prophylaxis preferences. METHODS: Electronic survey among pediatric hematologists members of three international subspecialty societies/consortia. RESULTS: Among 52 complete respondents (response rate, 42%), 47% of physicians reported treating 1-2 patients with SCD-associated VTE, while 20% treated 3-5 patients during the preceding 12 months. Most respondents (86%) estimated the risk of VTE recurrence at <5%. The vast majority (98%) of respondents prescribed anticoagulation for symptomatic VTE treatment. Duration of therapy varied by VTE type, 95% reported prescribing 6 weeks-3 months for provoked DVT, while 60% reported prescribing a similar duration for provoked PE with the remaining 40% reporting treating PE for longer duration. There was notable variation in the treatment practices for asymptomatic or unprovoked VTE. Lastly, half of physicians indicated to be "somewhat" (40%) and "not at all" (10%) confident making decisions regarding the duration and intensity of prophylactic anticoagulation. CONCLUSIONS: We identified significant variability in practice, a lower than expected perceived risk of recurrence, and uncertainty regarding VTE prophylaxis strategies in pediatric SCD. Cooperative multicenter studies are needed to generate evidence for future treatment guidelines development, and to identify opportunities for interventions aimed at managing and preventing VTE in pediatric SCD.

Current practices in pediatric hospital-acquired thromboembolism: Survey of the Children's Hospital Acquired Thrombosis (CHAT) Consortium.

Background: A rise in hospital-acquired venous thromboembolism (HA-VTE) in children has led to increased awareness regarding VTE prophylaxis and risk assessment. Despite no consensus exists regarding these practices in pediatrics. Objective: To describe common practices in VTE prophylaxis, VTE risk assessment models, and anticoagulation dosing strategies in pediatric hospitals that are members of the Children's Hospital Acquired Thrombosis (CHAT) Consortium. Methods: An electronic survey of 44 questions evaluating practices surrounding pediatric HA-VTE risk assessment and prevention was distributed between August 9, 2021, and August 30, 2021, to the primary investigators from the 32 institutions within the CHAT Consortium. Results: The survey response rate was 100% (n = 32). In total, 85% (n = 27) of the institutions assess HA-VTE, but only 63% (n = 20) have formal hospital guidelines. Within the institutions with formal guidelines, 100% (n = 20) include acute systemic inflammation or infection and presence of a central venous catheter (CVC) as risk factors for VTE. Pharmacologic prophylaxis is prescribed at 87% (28) of institutions, with enoxaparin being the most frequent (96%, n = 27). Variability in responses persisted regarding risk factors, risk assessment, thromboprophylaxis, dosing of prophylactic anticoagulation or anticoagulant drug monitoring. A majority of providers were comfortable providing thromboprophylaxis across all age groups. In addition, the global coronavirus disease 2019 increased the providers' use of prophylactic anticoagulation 78% (n = 25). Conclusion: Practices among institutions are variable in regard to use of HA-VTE prophylaxis, risk assessment, or guideline implementation, highlighting the need for further research and a validated risk assessment model through groups like the CHAT Consortium.

Acute Management of High-Risk and Intermediate-Risk Pulmonary Embolism in Children: A Review.

Severe forms of pulmonary embolism (PE) in children, althought rare, cause significant morbidity and mortality. We review the pathophysiologic features of severe (high-risk and intermediate-risk) PE and suggest novel pediatric-specific risk stratifications and an acute treatment algorithm to expedite emergent decision-making. We defined pediatric high-risk PE as causing cardiopulmonary arrest, sustained hypotension, or normotension with signs or symptoms of shock. Rapid primary reperfusion should be pursued with either surgical embolectomy or systemic thrombolysis in conjunction with a heparin infusion and supportive care as appropriate. We defined pediatric intermediate-risk PE as a lack of systemic hypotension or compensated shock, but with evidence of right ventricular strain by imaging, myocardial necrosis by elevated cardiac troponin levels, or both. The decision to pursue primary reperfusion in this group is complex and should be reserved for patients with more severe disease; anticoagulation alone also may be appropriate in these patients. If primary reperfusion is pursued, catheter-based therapies may be beneficial. Acute management of severe PE in children may include systemic thrombolysis, surgical embolectomy, catheter-based therapies, or anticoagulation alone and may depend on patient and institutional factors. Pediatric emergency and intensive care physicians should be familiar with the risks and benefits of each therapy to expedite care. PE response teams also may have added benefit in streamlining care during these critical events.

A Review of Venous Thromboembolism Risk Assessment and Prophylaxis in Plastic Surgery.

BACKGROUND: Venous thromboembolism is a significant cause of postoperative death and morbidity. While prophylactic and treatment regimens exist, they usually come with some risk of clinically relevant bleeding and, thus, must be considered carefully for each individual patient. METHODS: This special topic article represents a review of current evidence regarding venous thromboembolism risk, biology, and prevention in plastic surgery patients. The specific types and duration of available prophylaxis are also reviewed. The balance of venous thromboembolism risk must be weighed against the risk of hemorrhage. RESULTS: Though alternatives exist, the most validated risk assessment tool is the 2005 modification of the Caprini Risk Assessment Model. Controversies remain regarding recommendations for outpatient and low risk cosmetic patients. The authors additionally make recommendations for high-risk patients regarding the use of tranexamic acid, estrogen therapy, anesthesia, and prophylaxis regimens. CONCLUSION: Our profession has made great strides in understanding the science behind venous thromboembolism, risk stratification for patients, and prophylactic regimens; yet, continued studies and definitive data are needed.

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.

Rate of thrombosis in children and adolescents hospitalized with COVID-19 or MIS-C.

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is associated with thrombotic complications in adults, but the incidence of COVID-19-related thrombosis in children and adolescents is unclear. Most children with acute COVID-19 have mild disease, but coagulopathy has been associated with multisystem inflammatory syndrome in children (MIS-C), a postinfectious complication. We conducted a multicenter retrospective cohort study to determine the incidence of thrombosis in children hospitalized with COVID-19 or MIS-C and evaluate associated risk factors. We classified patients into 1 of 3 groups for analysis: COVID-19, MIS-C, or asymptomatic SARS-CoV-2. Among a total of 853 admissions (COVID-19, n = 426; MIS-C, n = 138; and asymptomatic SARS-CoV-2, n = 289) in 814 patients, there were 20 patients with thrombotic events (TEs; including 1 stroke). Patients with MIS-C had the highest incidence (9 [6.5%] of 138) vs COVID-19 (9 [2.1%] of 426) or asymptomatic SARS-CoV-2 (2 [0.7%] of 289). In patients with COVID-19 or MIS-C, a majority of TEs (89%) occurred in patients age ≥12 years. Patients age ≥12 years with MIS-C had the highest rate of thrombosis at 19% (9 of 48). Notably, 71% of TEs that were not present on admission occurred despite thromboprophylaxis. Multivariable analysis identified the following as significantly associated with thrombosis: age ≥12 years, cancer, presence of a central venous catheter, and MIS-C. In patients with COVID-19 or MIS-C, hospital mortality was 2.3% (13 of 564), but it was 28% (5 of 18) in patients with TEs. Our findings may help inform pediatric thromboprophylaxis strategies.

Bleeding Severity and Phenotype in 22q11.2 Deletion Syndrome-A Cross-Sectional Investigation.

OBJECTIVES: To prospectively quantify bleeding severity and elaborate hemorrhagic symptoms in children with 22q11.2 deletion syndrome (22q11DS) using 2 validated bleeding assessment tools (BATs), namely the Pediatric Bleeding Questionnaire and the International Society on Thrombosis and Hemostasis BAT (ISTH-BAT). We also sought to compare subjects' bleeding scores to unaffected first-degree family members. STUDY DESIGN: Children with 22q11DS and unaffected first-degree family members were recruited for the study. Two validated BATs were administered by a pediatric hematologist. Additional clinical and laboratory data were abstracted from patient medical records. Standard descriptive and nonparametric statistical methods were used. RESULTS: In total, 29 eligible subjects and controls were assessed. Median age (range) of subjects and controls was 8 (5-17) years and 38 (9-56) years, respectively. In total, 17 of 29 subjects had a positive bleeding score on ISTH-BAT compared with 1 of 29 control patients (P < .0001). Median ISTH-BAT score in subjects was 3 (0-12), compared with 2 (0-6) in control patients (P = .022). Median Pediatric Bleeding Questionnaire score in subjects was 2 (-1 to 12). The most frequent bleeding symptoms reported in subjects with 22q11DS were epistaxis (69%) and bruising (52%). Eighteen subjects had been surgically challenged, and 6 were noted to have increased perioperative hemorrhage. CONCLUSIONS: Children with 22q11DS have increased bleeding scores compared with their first-degree unaffected relatives. The majority of the bleeding symptoms described were mucocutaneous.

Unfractionated heparin using actual body weight without dose capping in obese pediatric patients-Subgroup analysis from an observational cohort study.

To evaluate the correlation between an uncapped, actual body weight-based unfractionated heparin dosing strategy, we performed a body mass index-based subanalysis of a previously reported pediatric cohort. Nearly half (45%) of obese patients were supra-therapeutic on initial anti-FXa assessment. Obese patients achieved therapeutic anti-FXa significantly faster than nonobese patients (median 4 vs 12 hours, P = .0192) and were more likely to have any supra-therapeutic anti-FXa levels (77% vs 35%; P = .0021). There was no statistically significant difference in major or clinically relevant nonmajor bleeding rates between weight categories (P = .69). Prospective pediatric studies are warranted to confirm our findings.