Pediatric pulmonary thromboembolism: a 3-year Canadian Pediatric Surveillance Program study

BACKGROUND

Pediatric pulmonary embolism (PE) is a rare event associated with significant morbidity and mortality. Awareness of clinical presentation and practices unique to children may aid clinicians in prompt identification and treatment.

OBJECTIVES

To describe the incidence, risk factors, clinical presentation, diagnostic and therapeutic practices, and short-term outcomes of pediatric PE.

METHODS

We conducted a 3-year national surveillance study through the Canadian Pediatric Surveillance Program. Over 2800 pediatric specialists and subspecialists were contacted monthly from 2020 to 2022 and requested to report all new cases of PE in patients up to 18 years of age. Case-specific data were obtained through voluntary completion of a detailed questionnaire.

RESULTS

Fifty-eight cases (78% female, n = 45) were reported (2.4 cases per million children), with rates highest in adolescents 15 to 18 years (6.6 cases per million). Detailed information, available for 31 (53%) cases, documented at least 1 risk factor in 28 (90%) cases; 24 (77%) patients presented with 2 or more symptoms. Computed tomography pulmonary angiography was used for diagnostic confirmation in 25 (81%) cases. Anticoagulation was initiated in 24 (77%) of 31 cases; fewer than 5 patients underwent thrombolysis or surgical interventions. Of 28 patients who received therapeutic interventions, 8 (29%) experienced treatment-related complications. Fewer than 5 mortalities were reported.

CONCLUSION

Pediatric PE is a rare event, with female adolescents at the highest risk. Although the presentation is often nonspecific, clinicians should maintain a high index of suspicion, particularly in patients with risk factors and when other diagnoses that may explain symptoms have been excluded.

Considerations for instituting pediatric pulmonary embolism response teams: A tool kit

The incidence of pediatric pulmonary embolism (PE) has increased by 200 % in the last decade, but at a single center, it is still infrequent. Given the unique epidemiologic features of pediatric PE, diagnosis is often delayed, and the management is empiric, based on individual physician experience or preference. Thus, there is a strong need for center-specific uniform management of pediatric PE patients. In adults, the development of pulmonary embolism response teams (PERTs) or PE critical care pathways has shortened the time to diagnosis and the initiation of definitive management. Evidence to support an improvement in PE outcomes after the development of PERTs does not exist in children. Nonetheless, we have summarized the practical practice guidelines that physicians and institutions can adopt to establish their institutional PERTs or critical pathways. We also provide strategies for resource-challenged institutions for partnering with centers with expertise in the management of pediatric PE.

Canadian clinical experience on switching from standard half-life recombinant factor VIII (rFVIII), octocog alfa, to extended half-life rFVIII, damoctocog alfa pegol, in persons with haemophilia A ≥ 12 years followed in a Comprehensive Hemophilia Care Program in Canada

INTRODUCTION

Damoctocog alfa pegol (BAY 94-9027, Jivi®) is an extended half-life recombinant factor (F)VIII replacement, indicated for the treatment of haemophilia A in patients aged ≥12 years. Following introduction of damoctocog alfa pegol in Canada in 2020, there have been no reports on routine clinical effectiveness and satisfaction, when switching from a previous FVIII product in Canada.

AIM

To report changes in pharmacokinetics, effectiveness, utilization and patient satisfaction when switching to damoctocog alfa pegol prophylaxis from previous standard half-life octocog alfa (BAY 81-8973, Kovaltry®) treatment.

METHODS

A single-centre, intra-patient comparison of pharmacokinetics and clinical outcomes was performed. Blood samples drawn once pre-dose and ≥2 times post-dose were measured by a one-stage assay to assess pharmacokinetic parameters including area under the curve (AUC, primary endpoint). Patient-reported outcomes data were collected using the Patient-Reported Outcomes, Burdens and Experiences questionnaire (PROBE). Clinical outcomes included annualized bleeding rate (ABR) and factor utilization.

RESULTS

Dose-normalized AUC was significantly increased after switch to damoctocog alfa pegol from octocog alfa. Median (quartile [Q]1; Q3) annualized bleeding rates were 0.67 (0.00; 1.33) with damoctocog alfa pegol and 1.33 (0.00; 2.67) with octocog alfa. Half of the patients receiving damoctocog alfa pegol prophylaxis experienced zero bleeds (n = 9, 50.0%) versus 38.9% (n = 7) of patients treated with octocog alfa. Patients' good quality of life was maintained.

CONCLUSION

This study provides routine clinical evidence supporting the benefits of switching from octocog alfa to damoctocog alfa pegol for patients with severe haemophilia A.

Development and validation of thromboembolism diagnostic algorithms in children with cancer from real-world data

OBJECTIVE

To evaluate the accuracy of diagnostic algorithms developed using the International Classification of Diseases (ICD-9-CM and ICD-10-CA) diagnostic codes and physician billing codes for thromboembolism (TE) from health administrative data compared to chart review diagnoses of TE in children with cancer.

METHODS

Using data linkage between the Pediatric Oncology Group of Ontario Network Information System (Ontario pediatric cancer registry) and various administrative data housed at ICES, eight algorithms were developed including a single reference to one of the billing codes, multiple references with varying time intervals, and combinations of various billing codes during primary cancer therapy for the whole cohort and, for early (<04/2002) and later (≥04/2002, solely ICD-10 codes) periods. Reference standard was chart review data from prior studies (from 1990 to 2016) among children (≤19 years) with cancer and radiologically confirmed TE.

RESULTS

Records of 2056 patients diagnosed with cancer at two participating sites during study period were reviewed; 112 had radiologically confirmed TE. The algorithm with addition of anticoagulation utilization codes was the best performing algorithm (sensitivity = 0.76;specificity = 0.85). With use of ICD-10 only codes, sensitivity of the same algorithm improved to 0.84 with specificity of 0.80.

CONCLUSION

This study provides a valid approach for ascertaining pediatric TE using real-world data.

IMPACT

Research in pediatric thrombosis, especially cancer-related thrombosis, is limited mainly due to small-sized studies. Real-world data provide ready access to large and diverse populations. However, there are no validated algorithms for identifying thrombosis in real-world data for children. An algorithm based on combination of thrombosis and anticoagulation utilization codes had 76% sensitivity and 85% specificity to identify diagnosis of thrombosis in children in administrative data. This study provides a valid approach for ascertaining pediatric thrombosis using real-world data and offers a good avenue to advance pediatric thrombosis research.

Simoctocog alfa (Nuwiq®) in previously untreated patients with severe haemophilia A-Final efficacy and safety results from the NuProtect study

INTRODUCTION

Simoctocog alfa (Nuwiq®) is a 4th generation recombinant FVIII with proven efficacy for the prevention and treatment of bleeding episodes (BEs) in previously treated patients with severe haemophilia A. The NuProtect study assessed the immunogenicity, efficacy and safety of simoctocog alfa in 108 previously untreated patients (PUPs). The incidence of high-titre inhibitors was 16.2% and no patients with non-null F8 mutations developed inhibitors.

AIM

To report the efficacy and safety results from the NuProtect study.

METHODS

PUPs received simoctocog alfa for prophylaxis, treatment of BEs, or as surgical prophylaxis. The efficacy of prophylaxis (during inhibitor-free periods) was assessed using annualised bleeding rates (ABRs). The efficacy in treating BEs and in surgical prophylaxis was assessed using a 4-point scale. Adverse events were recorded throughout the study.

RESULTS

Of 108 PUPs treated with simoctocog alfa, 103 received at least one prophylactic dose and 50 received continuous prophylaxis for at least 24 weeks. In patients on continuous prophylaxis, the median ABR was 0 (mean 0.5) for spontaneous BEs and 2.5 (mean 3.6) for all BEs. In 85 patients who had BEs, efficacy of BE treatment was excellent or good for 92.9% (747/804) of rated BEs; 92.3% of BEs were treated with 1 or 2 infusions. The efficacy of surgical prophylaxis was excellent or good for 94.7% (18/19) of rated procedures. There were no safety concerns and no thromboembolic events.

CONCLUSION

Simoctocog alfa was efficacious and well tolerated as prophylaxis, surgical prophylaxis and for the treatment of BEs in PUPs with severe haemophilia A.

Availability of Safe and Effective Therapeutic Options to Pregnant and Lactating Individuals Following the United States Food and Drug Administration Pregnancy and Lactation Labeling Rule

OBJECTIVE

To explore the extent and type of pregnancy and lactation data of newly approved prescription drugs and assess whether the presented recommendations are data-driven, as required by the US Food and Drug Administration Pregnancy and Lactation Labeling Rule implemented in 2015.

STUDY DESIGN

In this descriptive analysis, we reviewed pregnancy and lactation data of all new molecular entities approved between 2001 and 2020 in their most updated labeling. Information was collected regarding the pregnancy and lactation risk statements, the source of pregnancy and lactation data, and the design and methods of pregnancy and lactation studies in the labeling.

RESULTS

Of the 422 new molecular entities, the key advisory statement for use of 133 (32%) drugs in pregnancy and 194 (46%) drugs in lactation were classified as "against use." Less than 2% of all drugs had a key advisory statement that supported their use during pregnancy or lactation. The sources of data regarding use in pregnancy were studies in human and animals in 46 (11%) and 348 (82%) drugs, respectively. For use during lactation, data included studies in human and animals in 23 (5%) and 251 (59%) drugs, respectively. The key advisory recommendation was consistent with the available human information in 4 (8%) drugs in pregnancy and 3 (13%) drugs in lactation. Prescription drug labeling contains limited data to support informed decision-making for the use of prescription drugs during pregnancy/lactation. Close collaboration among stakeholders is required to enhance the availability of data in this population.

Do Children With an Allergic Transfusion Reaction Require Premedication For All Blood Products?

BACKGROUND

Children with a history of allergic transfusion reactions (ATRs) receive antihistamine premedication with or without hydrocortisone to prevent subsequent reactions. We aim to examine the frequency of developing ATRs to subsequent different blood product type transfusions.

METHODS

A retrospective chart review of children who received blood product transfusions (packed red blood cells, platelets, frozen plasma, intravenous immunoglobin, albumin, and cryoprecipitate) and developed ATRs. Cases were identified through Transfusion Transmitted Injuries Surveillance System- Ontario database with a complementary chart review. Demographics and subsequent transfusions records were described.

RESULTS

During this period, 35,925 blood products were transfused to 4153 patients. Thirty-eight ATRs were reported in 30 patients. All ATRs were minor except 1 anaphylaxis to albumin transfusion. Seven patients (23%) developed multiple ATRs, and all of them were of the same blood product type. A total of 60 subsequent different blood product types were transfused to the 7 patients who had multiple ATRs; none of those transfusions caused ATR.

CONCLUSION

In children with a history of ATR, developing a reaction to a different blood product type is rare. Hence, premedicating those transfusions is not warranted.

Long-term immunogenicity, efficacy and tolerability of simoctocog alfa in patients with severe haemophilia A who had completed the NuProtect study in previously untreated patients

BACKGROUND

The NuProtect study reported data on the immunogenicity, efficacy and tolerability of simoctocog alfa (Nuwiq^® ) in 108 previously untreated patients with severe haemophilia A planned to be treated for ≥100 exposure days or up to 5 years. The NuProtect-Extension study collected long-term prophylaxis data in children with severe haemophilia A.

METHODS

Patients who completed the NuProtect study according to the protocol were eligible for the NuProtect-Extension study, a prospective, multinational, non-controlled, Phase 3b study.

RESULTS

Of 48 patients who entered the extension study, 47 (median age 2.8 years) received prophylaxis with simoctocog alfa for a median of 24 months, with 82%-88% on a twice-weekly or less regimen. No patient developed FVIII inhibitors during the extension study. The median (IQR) annualized bleeding rate (ABR) during prophylaxis was 0 (0-0.5) for spontaneous bleeding episodes (BEs) and 1.00 (0-1.95) for all BEs. ABRs estimated using a negative binomial model were .28 (95% CI: .15, .53) for spontaneous and 1.62 (95% CI: 1.09, 2.42) for all BEs. During the median follow-up of 24 months, 34 (72%) patients had zero spontaneous BEs and 46 (98%) had zero spontaneous joint BEs. Efficacy in treating BEs was excellent or good for 78.2% of rated BEs, and efficacy of surgical prophylaxis was excellent for two rated surgeries. No treatment-related adverse events were reported.

CONCLUSION

No FVIII inhibitors developed during long-term prophylaxis in the NuProtect-Extension study. Prophylaxis with simoctocog alfa was efficacious and well-tolerated, and is therefore an attractive long-term option for children with severe haemophilia A.

Recombinant factor VIII Fc fusion protein for first-time immune tolerance induction: final results of the verITI-8 study

Inhibitor development remains a major challenge in factor VIII (FVIII) replacement therapy. verITI-8 is the first prospective study of a recombinant FVIII Fc fusion protein (rFVIIIFc; efmoroctocog alfa) for first-time immune tolerance induction (ITI) in males with severe hemophilia A and high-titer inhibitors (historical peak ≥5 Bethesda units [BU]/mL). In this single-arm, open-label, multicenter study, screening was followed by ITI (rFVIIIFc 200 IU/kg per day until tolerization or maximum of 48 weeks). Those who achieved ITI success entered a tapering period, returning to standard prophylaxis, and then entered follow-up. Primary end point was time to tolerization with rFVIIIFc defined by inhibitor titer <0.6 BU/mL, incremental recovery (IR) ≥66% of expected IR (IR ≥1.32 IU/dL per IU/kg), and half-life (t½) ≥7 hours within 48 weeks. Sixteen patients received ≥1 rFVIIIFc dose. Twelve (75%), 11 (69%), and 10 patients (63%), respectively, achieved negative inhibitor titers, an IR ≥66%, and a t½ ≥7 hours (ie, tolerance) within 48 weeks. Median times in weeks to achieve these markers of success were 7.4 (interquartile range [IQR], 2.2-17.8), 6.8 (IQR, 5.4-22.4), and 11.7 (IQR, 9.8-26.2), respectively. All patients experienced ≥1 treatment-emergent adverse event (TEAE), and 1 reported ≥1 related TEAE (injection site pain). Nine patients experienced ≥1 treatment-emergent serious AE. No thrombotic events, discontinuations because of AEs, or deaths were reported during the study. As the first extended half-life rFVIII with prospective data in ITI, rFVIIIFc offered short time to tolerization with durable responses in almost two-thirds of patients and was well tolerated. This trial was registered at www.clinicaltrials.gov as #NCT03093480.

BAY 81-8973 Efficacy and Safety in Previously Untreated and Minimally Treated Children with Severe Hemophilia A: The LEOPOLD Kids Trial

INTRODUCTION

 BAY 81-8973, a full-length recombinant factor VIII for hemophilia A treatment, has been extensively evaluated in previously treated patients in the LEOPOLD (Long-Term Efficacy Open-Label Program in Severe Hemophilia A Disease) clinical trials.

AIM

 To assess BAY 81-8973 efficacy and safety when used for bleed prophylaxis and treatment in previously untreated/minimally treated patients (PUPs/MTPs).

METHODS

 In this phase III, multicenter, open-label, uncontrolled study, PUPs/MTPs (<6 years old) with severe hemophilia A received BAY 81-8973 (15-50 IU/kg) at least once weekly as prophylaxis. Primary efficacy endpoint was the annualized bleeding rate (ABR) within 48 hours after prophylaxis infusion. Adverse events and immunogenicity were assessed. Patients who developed inhibitors were offered immune tolerance induction (ITI) treatment in an optional extension phase.

RESULTS

 Fifty-two patients were enrolled, with 43 patients (mean age: 13.6 months) treated. Median (interquartile range) ABR for all bleeds within 48 hours of prophylaxis infusion was 0.0 (0.0-1.8) among patients without inhibitors (n = 20) and 0.0 (0.0-2.2) among all patients. As expected, inhibitors were the most frequent treatment-related adverse event (high titer: 17 [39.5%] patients; low titer: 6 [13.9%] patients). Six of 12 patients who underwent ITI treatment in the extension phase (high titer [n = 5], low titer [n = 1]) achieved a negative inhibitor titer.

CONCLUSION

 BAY 81-8973 was effective for bleed prevention and treatment in PUPs/MTPs. The observed inhibitor rate was strongly influenced by a cluster of inhibitor cases, and consequently, slightly higher than in other PUP/MTP studies. Overall, the BAY 81-8973 benefit-risk profile remains unchanged and supported by ongoing safety surveillance. Immune tolerance can be achieved with BAY 81-8973.

Physiotherapist performed Point of Care Ultrasonography (POCUS): a scoping review of 209 studies

BACKGROUND

Point of care ultrasonography (POCUS) is a non-ionizing imaging technique that is emerging in physiotherapy practice.

OBJECTIVE

To systematically map the research literature on physiotherapist performed POCUS.

DATA SOURCES

Following PRISMA-ScR guidelines, OVID Medline, CINAHL, AMED, and EMBASE were searched.

ELIGIBILITY CRITERIA

Peer-reviewed publications of physiotherapist performed POCUS were included.

DATA EXTRACTION AND DATA SYNTHESIS

Data collected included: title, author(s), journal, year of publication, design of included studies, sample size, age category of the sample, anatomical area of POCUS, geographical location of research, study setting, and disease condition/patient population. Data analysis consisted of descriptive statistics for the key characteristics of each research question.

RESULTS

A total of 18 217 titles and abstracts and 1 372 full-text citations were screened, with 209 studies included. Most included studies were measurement studies that assessed the psychometric properties of POCUS in adult patients, were published in the United States of America and imaged the abdominal lumbo-pelvic region. Eighty-two percent of studies were published in the last 10 years.

LIMITATIONS

Non-English language, review articles and grey literature were excluded for feasibility. Studies were excluded if it was not clearly reported that a physiotherapist performed the POCUS.

CONCLUSION

This review identified a wide variety of practice settings and a diverse number of patient conditions in which physiotherapists are performing POCUS. This breadth and depth of this review highlighted the need for improved reporting of study methodology and key areas of future research in physiotherapy performed POCUS. CONTRIBUTION OF THE PAPER.

Practical Implications of KRAS Mutation Status and Sidedness of Primary Tumour in Patients with Colorectal Cancer and Synchronous Liver Metastases: A Subset Analysis of the CoSMIC Study

Patients with colorectal cancer presenting with synchronous liver metastases have less favourable outcomes than those with primary-only disease. There is evidence of different genetic mutational signatures according to the sidedness of the primary tumour. KRAS mutations are key driver mutations in colorectal cancer progression. This post hoc analysis of the previously reported CoSMIC inception cohort explores the association between primary tumour sidedness and KRAS mutational status on the outcome of patients with colorectal cancer and synchronous liver metastases. Patients diagnosed with synchronous disease were recruited between April 2014 and March 2017 and, after exclusions, 83 patients undergoing colorectal primary KRAS mutation testing constituted the final study population. Data were collected prospectively on demographic profiles, treatment, and outcomes. Twenty-one patients (25%) had right-sided tumours and 62 (75%) had left-sided tumours, with 46 (55%) and 37 (45%) exhibiting wildtype and mutated KRAS, respectively. There was no difference in distribution of liver metastases by KRAS status (unilobar vs. bi-lobar; p = 0.58; Fisher’s Exact test) and no difference in 5-year survival according to KRAS mutation status (Log-rank test, p = 0.82) or tumour sidedness (p = 0.16). In summary, in this cohort of patients with colorectal cancer and synchronous liver metastases, neither KRAS mutation status nor tumour sidedness influenced survival.

Cord-Blood High-Sensitivity Troponin-I Reference Interval and Association with Early Neonatal Outcomes

OBJECTIVE

This study was aimed to establish a reference interval for high-sensitivity cardiac troponin I (hs-cTnI) in umbilical cord blood of infants and to assess its association with the risk of predetermined early neonatal outcomes in a high-acuity tertiary care hospital.

STUDY DESIGN

Umbilical cord-blood samples were collected and hs-cTnI was measured in all infants born between August 2015 and September 2015 at McMaster Children's Hospital (n = 256). Gestational age, birth weight, Apgar's scores, age in days at which feeding was established, neonatal intensive care unit (NICU) admission, and discharge in days after birth were recorded.

RESULTS

The 90th, 95th, and 99th percentiles for the term infant subcohort were 19.75, 41.45, and 166.30 ng/L, respectively. We observed decreased mean gestational ages and birth weights in both the 90th (37.7 weeks; 2,961.4 g) and 95th percentiles (37.1 weeks; 2,709.9 g) when compared with the remaining infants. Moreover, levels of hs-cTnI were significantly higher in infants with respiratory distress requiring intervention (p < 0.05), low birth weight infants (p < 0.01), preterm infants (p < 0.001), and those requiring NICU admission (p < 0.01). Multiple linear regression of the recorded demographic factors revealed prematurity (gestational age <35 weeks: coefficient 0.346 ± 0.160, p < 0.05; gestational age <37 weeks: coefficient 0.253 ± 0.105, p < 0.05) and male sex (coefficient 0.138 ± 0.047; p < 0.01) to be most predictive of log-hs-cTnI levels.

CONCLUSION

This study establishes the reference values for cord-blood hs-cTnI in infants at a tertiary care center. Premature and sick infants requiring NICU admission had significantly higher levels of hs-cTnI.

KEY POINTS

· Established the 90th, 95th, and 99th percentiles of neonatal cord-blood hs-cTnI in term infants as 19.75, 41.45, and 166.30 ng/L, respectively.. · Infants with hs-cTnI levels exceeding the 90th percentile had lower gestational ages and birth weights with higher rates of NICU admissions.. · Infants with respiratory distress or requiring NICU admission were found to have higher levels of hs-cTnI..

A retrospective cohort study examining health care utilization patterns in individuals diagnosed with an eating disorder in childhood and/or adolescence

OBJECTIVE

This study examined a 2-year period following an eating disorder (ED) diagnosis in order to determine patterns of health care utilization.

METHOD

We conducted a retrospective cohort study of children (n = 1560) diagnosed with an ED between 2000 and 2017. The ED diagnosis was made at a tertiary level hospital for children and adolescents presenting for outpatient assessment by specialist adolescent medicine physicians and recorded in a program database over this period of time. We then created three sex- and age-matched comparison cohorts using provincial health administrative databases including: a general population cohort, a diabetes cohort (to compare nonmental health care utilization) and a mood disorder cohort (to compare mental health care utilization). Outcomes included hospitalizations, emergency department visits, as well as general practitioner, psychiatrist, and pediatrician visits. Odds ratios (dichotomous outcomes) and rate ratios (continuous outcomes) were calculated.

RESULTS

Compared to the general population cohort, the ED cohort had higher odds and rates of all types of health care utilization. Compared to the diabetes cohort, the ED cohort had higher odds of nonmental health-related admissions (OR 1.45, 95% CI 1.09-1.95) and higher rates of nonmental health-related emergency department visits (RR 1.59, 95% CI 1.18-2.13). Compared to the mood disorder cohort, the ED cohort had higher rates of pediatrician visits, which were mental health-related (RR 14.88, 95% CI 10.64-20.82), however most other types of mental health service utilization were lower.

DISCUSSION

These patterns indicate that the service needs of young people diagnosed with EDs are higher than those with diabetes with respect to nonmental health admissions and emergency department visits, while in terms of mental health service utilization, there appears to be a lack of use of mental health services compared to youth with mood disorders with the exception of pediatrician mental health visits. These findings must be interpreted in the context of under-detection and under-treatment of EDs.

PUBLIC SIGNIFICANCE STATEMENT

Our study found that the health service needs of young people with EDs are higher than those with diabetes with respect to admissions and emergency department visits, while there appears to be a lack of use of mental health services compared to youth with mood disorders with the exception of pediatrician mental health visits.

Risk factors for neonatal thrombosis: A retrospective study conducted in a single Canadian intensive care unit

Among children, neonates have the highest incidence of thrombosis. We conducted a retrospective review of neonatal thrombosis, in a single intensive care unit (ICU) over 4.5 years. Among 4860 ICU admissions to our center, identified through the Canadian Neonatal Network database, 186 were associated with arterial and venous thrombosis involving 195 thrombotic sites. The neonatal thrombosis incidence was 38 per 1000 neonatal ICU admissions. We assessed patient characteristics and compared the association between risk factors and thrombosis. In the multivariate analysis, central venous catheters, sepsis, and respiratory distress syndrome were significant predictors of neonatal thrombosis.

Use of thrombolytic agents to treat neonatal thrombosis in clinical practice

Among children, neonates have the highest incidence of thrombosis. Thrombolytic agents are used for the management of life and/or organ-threatening thrombosis. Literature on the efficacy and safety of thrombolytic agents in neonates is limited. We reviewed the evidence on dosing, administration, monitoring and treatment duration of tissue plasminogen activator (tPA), streptokinase and urokinase (URK) in neonates (≤ 28days). A systematic literature search was conducted of current databases from inception until 31 March 2021. The initial search yielded 6881 articles and 18 were retained for review. tPA, streptokinase and URK was utilized in 12, seven and four studies on 115, 51 and 16 patients, respectively. The dose range for tPA, streptokinase and URK was 0.01 -0.6 mg/kg/h, 50-2000 and 1000-0 000 units/kg/h, respectively, and treatment duration ranged from 30 min to 30 days. This is the first study to objectively summarize the efficacy and safety of thrombolytic agents in neonates. Overall, thrombolysis was associated with 87.9% complete or partial thrombus resolution and 7.4% recurrence risk. The bleeding risk associated with thrombolytic agents was 23.1% on pooled analysis, which is higher than other anticoagulants. Larger prospective studies are required to determine effective dosing regimens of these therapeutic drugs and further clarify their efficacy and safety. Blood Coagul Fibrinolysis 33:000-000 Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.

Epidemiology, diagnosis and management of neonatal thrombosis: a single-center cohort study

The incidence of neonatal venous and arterial thrombosis ranges from 6.9 to 15/1000 neonatal ICU (NICU) admissions, and is likely an underestimate based on population demographics, frequency of surveillance and vascular catheterization. This retrospective study involving 234 infants reviewed the epidemiology, diagnosis, and management of neonatal thrombosis in a single, tertiary care institution over more than 10 years. The incidence of thrombosis was 25/1000 NICU admissions, with a preterm to term infant ratio of 1.5 : 1 and a slightly higher proportion of male sex (55.1%). The mean (range) gestational age and birth weight was 33.8 weeks (23-41.6) and 2360 g (512-5890). The median age (IQR) of thrombus diagnosis was 7 (3-17) days. Portal vein thrombosis was most prevalent (59.4%) compared with other sites of thrombosis. Almost three-quarter (171/234; 73.1%) of the thrombotic episodes were line-related, while infection and surgery were associated with 19.7% (46/234) and 10.7% (25/234), respectively. Twenty patients (8.3%) were screened for thrombophilia and 3 were positive; 2 for antithrombin deficiency, 1 for factor V Leiden gene mutation. Subjects were followed with imaging for 3 months with a treatment duration, mean (IQR) of 33.5 (10.8-42.5) days. Complete clot resolution was significantly higher in the anticoagulation group (48%; 17%; P = 0.03) compared with untreated patients. No group difference was noted for partial thrombus resolution (33.3%; 12.4%; P = 0.313). Anticoagulation halted thrombus progression (2.6 versus 12.4%; P = 0.025) and fewer treated patients failed to attend follow-up visits (6.5 versus 18.6%; P = 0.022). Well designed, multicenter prospective studies with larger sample sizes are required to confirm these findings.

How to use low-molecular-weight heparin to treat neonatal thrombosis in clinical practice

Among children, neonates have the highest incidence of thrombosis due to risk factors such as catheter instrumentation, an evolving coagulation system and congenital heart disease. Low-molecular-weight heparins (LMWHs) are the most commonly used anticoagulants in neonates. Published guidelines delineate dosing and monitoring protocols for LMWH therapy in newborns. However, challenging clinical situations frequently present that warrant healthcare providers to think critically beyond the range of guidelines, and judiciously resolve specific problems. This review describes the use of LMWH in the neonatal population, including practical aspects such as route and site of administration, preparation from concentrated formulations and methods to minimize pain of subcutaneous injection. It is followed by a discussion on dosing, monitoring and outcomes of LMWH therapy in neonates. The risk of recurrence of thrombosis in neonates after LMWH therapy is approximately 3% based on a pooled analysis of studies reporting this outcome over the last 24 years. The article concludes with an overview of the side-effects of LMWH, including the risk of bleeding which is around 4% based on pooled analyses of more than 30 studies.

Management of Colorectal Cancer with Synchronous Liver Metastases: An Inception Cohort Study (CoSMIC)

BACKGROUND

Approximately one-fifth of patients with colorectal cancer present with hepatic metastases. There are limited prospective data on the outcomes of synchronous combined liver and bowel surgery and liver-first or bowel-first routes where contemporary chemo(radio)therapy is integrated into management.

METHODS

Between 1 April 2014 and 31 March 2017, 125 patients with colorectal cancer and synchronous liver metastases were recruited. Data are reported on pathway-specific outcomes, including perioperative complications, treatment completion, and overall and disease-free survival. The study was registered with ClinicalTrials.gov (NCT02456285).

RESULTS

There was no difference in age, body mass index, or Charlson score between surgical groups. Neoadjuvant chemotherapy was used in 50 (40%) patients for a mean duration of 4.6 months (standard deviation [SD] 5.4), and mean time from completion of chemotherapy to surgery was 2.6 months (SD 1.9). Complications were similar between patients completing the synchronous and staged pathways (p = 0.66). Mean total inpatient stay was 16.5 days (SD 8.1) for staged surgery compared with 16.8 days (SD 10.3) for the synchronous group (t-test; p = 0.91). There was no difference in time to treatment completion between pathways. Thirty six (35%) patients were disease-free at 12 months, with no significant difference between groups (Chi-square, p = 0.448). Quality of life was similar in all surgical groups.

CONCLUSIONS

Perioperative complications and oncological and healthcare occupancy outcomes are equivalent between patients completing staged and synchronous pathways for the management of patients with colorectal cancer and synchronous liver metastases. Future studies should focus on optimizing the criteria for pathway selection, incorporation of cancer genomics data, and patient (user) preferences.

Management of Anticoagulation Therapy in Patients With Thromboembolism in the Context of Renal Dysfunction: Challenging Cases and Practical Algorithms

BACKGROUND

Low-molecular-weight heparin is cleared through the kidneys and is commonly used for anticoagulation in the pediatric population.

OBSERVATION

We present 3 challenging cases of children requiring anticoagulation in the context of acute kidney injury, nephrotic syndrome, and hemodialysis.

CONCLUSIONS

A significant change in anti-factor Xa (anti-Xa) levels-used for drug monitoring-should prompt an assessment of renal function. In nephrotic syndrome, anti-Xa levels should be closely monitored when there is a change in the status of nephrotic disease activity. In hemodialysis patients, enoxaparin at once daily reduced dosing should be considered with trough and peak anti-Xa levels monitoring.

Effect of unfractionated heparin and low molecular weight heparin on the clotting of platelet-reduced whole blood: an in-vitro study utilizing thromboelastography

Treatment of venous thromboembolism with concomitant thrombocytopenia is challenging. The platelet threshold for safe administration of anticoagulants is under debate, with minimum platelet count of 50 × 109/l being recommended as the safe cutoff. However, some evidence suggests administration of anticoagulants may still be safe at platelet levels of 30 × 109/l. Therefore, we developed an in-vitro thromboelastography (TEG) study to examine the effect of therapeutic or prophylactic levels of unfractionated heparin (UFH) and low molecular weight heparin (LMWH) on the clotting profile of platelet-reduced whole blood. Using magnetic bead-based antibody chromatography, platelets were removed to achieve platelet-depleted blood (<10 × 109/l of platelets). Platelet-depleted blood was then mixed with whole blood to produce blood samples with platelet counts of 30 × 109, 50 × 109 and 150 × 109/l. These blood samples were incubated with therapeutic or prophylactic levels of UFH or LMWH in disposable TEG cups. Clotting was initiated with 10 mmol/l calcium and optimized tissue factor levels for each anticoagulant used (2.25 pmol/l for UFH and 2.05 pmol/l for LMWH). Clotting was monitored by TEG at 37 °C for 180 min. The following TEG parameters were evaluated: R (time to clot), maximum amplitude (strength of clot) and area under the curve in 15 min (overall speed and strength of the clot at 15 min of clotting). No statistically significant differences were observed between platelet counts of 30 × 109 and 50 × 109/l for R, maximum amplitude or area under the curve in 15 min for most of the therapeutic and prophylactic doses of UFH and LMWH tested in this study. Use of anticoagulants compromised all of the TEG parameters relative to a normal platelet count of 150 × 109/l, in a dose dependent manner. The current study demonstrates that in-vitro clotting is impaired with use and increasing doses of anticoagulants. Despite this observation, we did not observe a significant difference in clotting between platelet levels of 30 × 109 and 50 × 109/l. Overall, this work provides further insight in the debated use of anticoagulants in patients with venous thromboembolism and concomitant thrombocytopenia, and provides support for possible use of anticoagulants at lower platelet thresholds.

Central venous catheters are an important factor in paediatric thrombosis

AIM

To establish the incidence and characteristics of paediatric thrombosis (PT) in a Canadian tertiary care centre during the era of low molecular weight heparin (LMWH).

METHODS

A retrospective observational case study of all patients <18 years of age evaluated for arterial and venous thrombosis from May 2008 to July 2018 at McMaster Children's Hospital was conducted through the electronic medical record.

RESULTS

The incidence of PT was 52.2 per 10 000 hospital admissions (n = 477/91 462). Provoked thrombosis was more prevalent (88.9%, n = 424/477) than unprovoked (2.9%, n = 14/477) or idiopathic thrombosis (4%, n = 19/477). Half of PT were in children <2 years (51.2%, n = 244/477). Central vascular catheterisation was a contributory factor in more than half of thrombotic events (56.2%, n = 268/477), while trauma (1.1%, n = 5/477), oral contraceptives (4%, n = 19/477), infection (4%, n = 19/477), surgery (6.9%, n = 33/477) and malignancy (8.4%, n = 40/477) were also risk factors. Arterial ischaemic stroke was diagnosed in 11.1% of cases (n = 53/477), while pulmonary embolism was identified in 7.1% (n = 34/477) and 1.7% of cases were fatal (n = 8/477). LMWH was the first-line therapeutic of choice (47.8%, n = 228/477), with 28.1% (n = 134/477) requiring no intervention.

CONCLUSION

These data reiterate the elevated thrombosis risk to which infants and children with central vascular access are exposed.

Simoctocog Alfa (Nuwiq) in Previously Untreated Patients with Severe Haemophilia A: Final Results of the NuProtect Study

Introduction  FVIII inhibitor development is the most serious contemporary treatment complication in haemophilia A, particularly in previously untreated patients (PUPs). No inhibitors developed in clinical trials in previously treated patients treated with simoctocog alfa (Nuwiq), a fourth-generation recombinant FVIII produced in a human cell line.

Methods  The NuProtect study investigated the immunogenicity of simoctocog alfa in PUPs. NuProtect was a prospective, multinational, open-label, non-controlled, phase III study. PUPs with severe haemophilia A (FVIII:C <1%) of any age and ethnicity were treated with simoctocog alfa for 100 exposure days or a maximum of 5 years. Patients were true PUPs without prior exposure to FVIII concentrates or blood components. Inhibitor titres were measured with the Nijmegen-modified Bethesda assay; cut-off for positivity was 0.6 BU mL ⁻¹ (≥0.6 to <5 low-titre, ≥5 high titre).

Results  A total of 108 PUPs with a median age at first treatment of 12.0 months (interquartile range: 8.0–23.5) were treated with simoctocog alfa. F8 mutation type was known for 102 patients (94.4%) of whom 90 (88.2%) had null F8 mutations and 12 (11.8%) had non-null mutations. Of 105 PUPs evaluable for inhibitor development, 28 (26.7%) developed inhibitors; 17 high titre (16.2%) and 11 low titre (10.5%). No PUPs with non-null F8 mutations developed inhibitors.

Conclusion  In the NuProtect study, the rate of inhibitor development in PUPs with severe haemophilia A treated with simoctocog alfa was lower than the rate reported for hamster-cell-derived recombinant factor VIII products in other recent clinical trials. No inhibitors were reported in PUPs with non-null F8 mutations.

Heparin-Induced Thrombocytopenia in a Pediatric Population: Implications for Clinical Probability Scores and Testing

OBJECTIVES

To determine the applicability of the 4Ts score and the Heparin-Induced Thrombocytopenia (HIT) Expert Probability (HEP) score in children with suspected HIT and to estimate the number of children potentially at risk of HIT.

STUDY DESIGN

We retrospectively estimated 4Ts and HEP scores in a cohort of 50 children referred for laboratory screening with enzyme immunoassay. In addition, minor modifications were introduced to the 4Ts score (modified 4Ts score) to adapt it for use in the pediatric setting. All patients with positive enzyme immunoassays were tested with serotonin release assay. We also extracted the number of patients started on heparins in a similar period of time.

RESULTS

The median age at the time of testing was 4 years (25th-75th percentile, 8.7 months to 13.5 years); 78% of patients had low and 22% had intermediate risk pretest probability scores using the original 4Ts score; 86% had low risk and 14% had intermediate risk scores using the modified 4Ts score; 54% of children had a HEP score of ≥2. Six patients (12%) had a positive (≥0.40 optical density units) enzyme immunoassay, but none had a positive serotonin release assay. Based on anticoagulation dose, there were 1-2 new daily potentially high-risk exposures to heparinoids at our institution.

CONCLUSIONS

The modified 4Ts and original 4Ts scores may be more adequate than the HEP score to determine HIT pretest probability in children. Despite the number of patients potentially at risk, HIT is rare in pediatrics.

Potential Risk Factors Contributing to Development of Venous Thromboembolism for Total Knee Replacements Patients Prophylaxed With Rivaroxaban: A Retrospective Case-Control Study

Rivaroxaban after total knee arthroplasty (TKA) is used to prevent postoperative venous thromboembolism (VTE); however, despite thromboprophylaxis, some patients still develop postoperative VTE. To determine whether tourniquet time, time to initiate rivaroxaban (TTI_RIV), or Body Mass Index (BMI) was associated with postoperative VTE. A retrospective case-control study was conducted. Those patients that developed VTE despite prophylaxis (cases) were compared to controls (no VTE). A univariate analysis was conducted (p < 0.05 statistically significant). Seven VTE cases were identified from 234 TKA-patients. Patients with and without VTE had BMI of 40.1 ± 9.1 and 32.8 ± 7.5, respectively (p = 0.064). TTI_RIV in VTE and control group was 28.2 ± 4.7 hours and 26.4 ± 4.2 hours, respectively (p = 0.39). Mean tourniquet time in VTE and control group was 65.0 ± 8.7 minutes and 49 ± 8.8 minutes, respectively (p = 0.0007). Statistically significant differences in tourniquet times were noted between VTE and non-VTE group but not for TTI_RIV and BMI. Prolonged tourniquet use could pose a potential risk factor for postoperative VTE. Thromboprophylaxis management may need to be adjusted, based on patient-specific factors that could include increasing doses of oral anticoagulants and/or mechanical prophylaxis. However, further large-scale studies are required to establish pathophysiology.

Rivaroxaban for treatment of pediatric venous thromboembolism. An Einstein-Jr phase 3 dose-exposure-response evaluation

BACKGROUND

Recently, the randomized EINSTEIN-Jr study showed similar efficacy and safety for rivaroxaban and standard anticoagulation for treatment of pediatric venous thromboembolism (VTE). The rivaroxaban dosing strategy was established based on phase 1 and 2 data in children and through pharmacokinetic (PK) modeling.

METHODS

Rivaroxaban treatment with tablets or the newly developed granules-for-oral suspension formulation was bodyweight-adjusted and administered once-daily, twice-daily, or thrice-daily for children with bodyweights of ≥30, ≥12 to <30, and <12 kg, respectively. Previously, these regimens were confirmed for children weighing ≥20 kg but only predicted in those <20 kg. Based on sparse blood sampling, the daily area under the plasma concentration-time curve [AUC(0-24)ss ] and trough [Ctrough,ss ] and maximum [Cmax,ss ] steady-state plasma concentrations were derived using population PK modeling. Exposure-response graphs were generated to evaluate the potential relationship of individual PK parameters with recurrent VTE, repeat imaging outcomes, and bleeding or adverse events. A taste-and-texture questionnaire was collected for suspension-recipients.

RESULTS

Of the 335 children (aged 0-17 years) allocated to rivaroxaban, 316 (94.3%) were evaluable for PK analyses. Rivaroxaban exposures were within the adult exposure range. No clustering was observed for any of the PK parameters with efficacy, bleeding, or adverse event outcomes. Results were similar for the tablet and suspension formulation. Acceptability and palatability of the suspension were favorable.

DISCUSSION

Based on this analysis and the recently documented similar efficacy and safety of rivaroxaban compared with standard anticoagulation, we conclude that bodyweight-adjusted pediatric rivaroxaban regimens with either tablets or suspension are validated and provide for appropriate treatment of children with VTE.

Outcomes following neonatal portal vein thrombosis: A descriptive, single-center study and review of anticoagulant therapy

BACKGROUND

Neonatal portal vein thrombosis (PVT) is uncommon with potentially serious complications that may manifest in infancy and childhood.

OBJECTIVE

The primary aim of our study was to describe the short-term and long-term outcomes of neonatal PVT.

METHODS

A retrospective chart review was conducted from 2008 to 2016 of neonates diagnosed with PVT. A systematic review was also performed from 2000 to 2018 to evaluate anticoagulant therapy (ACT) in neonatal PVT.

RESULTS

Forty-four premature and 30 term infants (mean gestational age 30.7 vs 39.1 weeks, respectively) had PVT. Sixty-eight involved the left portal vein, one involved only the main portal vein, and 5 involved ≥1 vein. PVT was catheter associated in 46 (62%); none of the 7 neonates tested had thrombophilia. Of 74 neonates, 19 (26%) received ACT and 55 (74%) were untreated. The mean follow-up duration was 16.6 months (SD = 17.62; range, 0-89.6); 59.5% were followed for ≥6 months. On last ultrasound examination, thrombus resolution was documented in treated (ACT; n = 19) and nontreated (n = 55) neonates: 12 (63%) versus 32 (58%) with complete resolution, 1 (5%) versus 6 (11%) partial, 0 versus 1 (2%) extension, and 6 (32%) versus 16 (29%) had nonprogressive lesions, respectively. Seventy-one (96%) had no complications. Seventy-one articles met inclusion criteria for the systematic review and 19 were retained for analysis after assessment.

CONCLUSIONS

PVT resolution rate was similar to previous reports. Although a low complication rate was detected, longer follow-up is necessary to determine the need for early treatment and the precise incidence of outcomes such as portal hypertension.

Feasibility and safety of delivering full-dose anticoagulation therapy in children treated according to Dana-Farber Cancer Institute acute lymphoblastic leukemia consortium therapy protocols

BACKGROUND

The literature is void of an evidence-based anticoagulation therapy (ACT) management strategy in the context of thrombocytopenia. We examined the impact of thrombocytopenia on low-molecular-weight heparin (LMWH) dosing and incidence of bleeding in children with acute lymphoblastic leukemia (ALL) or lymphoblastic lymphoma (LL) who developed thromboembolism (TE) during therapy according to DFCI ALL protocols.

PROCEDURE

Patient records from our tertiary care center were reviewed for demographics, details of diagnoses and therapy of ALL/LL and TE diagnoses, platelet counts during ACT, LMWH dosing, and bleeding episodes.

RESULTS

Thirty-nine TEs were diagnosed in 33 patients [mean age 9 years (range, 2.5-18); 16 males and 31 with ALL] during the study period. A majority (85%) of patients were diagnosed with TE in the consolidation phase with mean time to TE 5.75 months from ALL/LL diagnosis. All patients received LMWH, and the median duration of ACT was 5.9 months (range, 1-11 months). Platelets were measured weekly. On 29 occasions, platelet nadir was <50 × 10⁹ /L, and twice it was < 20 × 10⁹ /L. One (3%) patient had major bleeding episode while on ACT. Platelet count at the time of bleeding was 222 × 10⁹ /L. Ninety-two procedures [83 lumbar punctures (LPs), 9 central venous line (CVL) insertion/revision] were completed without bleeding complications. Asparaginase was held temporarily with TE diagnosis in 48% of patients; most (88%) patients completed all scheduled doses as per protocol.

CONCLUSIONS

Ability to administer full-dose LMWH, expected bleeding rate, and completion of asparaginase doses while on ACT suggest full-dose ACT is feasible and safe in children with ALL/LL who develop TE during DFCI ALL consortium therapy protocols.

American Society of Hematology 2018 Guidelines for management of venous thromboembolism: treatment of pediatric venous thromboembolism

BACKGROUND

Despite an increasing incidence of venous thromboembolism (VTE) in pediatric patients in tertiary care settings, relatively few pediatric physicians have experience with antithrombotic interventions.

OBJECTIVE

These guidelines of the American Society of Hematology (ASH), based on the best available evidence, are intended to support patients, clinicians, and other health care professionals in their decisions about management of pediatric VTE.

METHODS

ASH formed a multidisciplinary guideline panel that included 2 patient representatives and was balanced to minimize potential bias from conflicts of interest. The McMaster University GRADE Centre supported the guideline-development process, including updating or performing systematic evidence reviews (up to April of 2017). The panel prioritized clinical questions and outcomes according to their importance for clinicians and patients. The panel used the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach, including GRADE Evidence-to-Decision frameworks, to assess evidence and make recommendations, which were subject to public comment.

RESULTS

The panel agreed on 30 recommendations, covering symptomatic and asymptomatic deep vein thrombosis, with specific focus on management of central venous access device-associated VTE. The panel also addressed renal and portal vein thrombosis, cerebral sino venous thrombosis, and homozygous protein C deficiency.

CONCLUSIONS

Although the panel offered many recommendations, additional research is required. Priorities include understanding the natural history of asymptomatic thrombosis, determining subgroup boundaries that enable risk stratification of children for escalation of treatment, and appropriate study of newer anticoagulant agents in children.

A Practical Guide to the Management of the Fetus and Newborn With Hemophilia

Newborns with hemophilia are at risk of intracranial hemorrhage, extracranial hemorrhage, and other bleeding complications. The safe delivery of a healthy newborn with hemophilia is a complex process that can begin even before conception, and continues throughout pregnancy, birth, and the newborn period. This process involves the expectant parents and a wide variety of health-care professionals: genetic counselors, obstetricians, neonatologists, pediatricians, radiologists, adult and pediatric hematologists, and nurses with expertise in hemophilia. Because of this multidisciplinary complexity, the relative rarity of births of newborns with hemophilia, and the lack of high-quality evidence to inform decisions, there is considerable variation in practice in this area. We present a comprehensive multidisciplinary approach, from preconception counseling to discharge planning after birth, and describe available options for management decisions. We highlight a number of areas of important uncertainty and controversy, including the preferred mode of delivery, the appropriate use and timing of neuroimaging tests, and the appropriate use of clotting factor concentrates in the newborn period. While the approach presented here will aid clinicians in planning and providing care, further research is required to optimize the care of newborns with hemophilia.

Pediatric superior vena cava syndrome: An evidence-based systematic review of the literature

Superior vena cava syndrome (SVCS) results in vascular, respiratory, and neurologic compromise. A systematic search was conducted to determine the prevalence of pediatric SVCS subtypes and identify clinical characteristics/treatment strategies that may influence overall outcomes. Data from 101 case reports/case series (142 patients) were analyzed. Morbidity (30%), mortality (18%), and acute complications (55%) were assessed as outcomes. Thrombosis was present in 36%, with multi-modal anticoagulation showing improved outcome by >50% (P = 0.004). Infant age (P = 0.04), lack of collaterals (P = 0.007), acute complications (P = 0.005), and clinical presentation may have prognostic utility that could influence clinical decisions and surveillance practices in pediatric SVCS.

Coagulation and Fibrinolytic Profile of Paediatric Patients Undergoing Cardiopulmonary Bypass

The haemostatic system and the use of heparin during cardiopulmonary bypass (CPB) have been studied extensively in adults but not in children. Results from adult trials cannot be extrapolated to children because of age-dependent physiologic differences in haemostasis. We studied 22 consecutive paediatric patients who underwent CPB at The Hospital for Sick Children, Toronto. Fibrinogen, factors II, V, VII, VIII, IX, XI, XII, prekallikrein, protein C, protein S, antithrombin (AT), heparin cofactor II, α2-macroglobulin, plasminogen, α2-antiplas- min, tissue plasminogen activator (tPA), plasminogen activator inhibitor, thrombin-AT complexes (TAT), D-dimer, heparin (by both anti-factor Xa assay and protamine titration) and activated clotting time (ACT) were assayed perioperatively. The timing of the sampling was: pre heparin, post heparin, after initiation of CPB, during hypothermia, post hypothermia, post protamine reversal and 24 h post CPB. Plasma concentrations of all haemostatic proteins decreased by an average of 56% immediately following the initiation of CPB due to haemodilution. During CPB, the majority of procoagulants, inhibitors and some components of the fibrinolytic system (plasminogen, α2AP) remained stable. However, plasma concentrations of TAT and D-dimers increased during CPB showing that significant activation of the coagulation and fibrinolytic systems occurred. Mechanisms responsible for the activation of haemostasis are likely complex. However, low plasma concentrations of heparin (<2.0 units/ml in 45% of patients) during CPB were likely a major contributing etiology. ACT values showed a poor correlation (r = 0.38) with heparin concentrations likely due to concurrent haemodilution of haemostatic factors, activation of haemostatic system, hypothermia and activation of platelets. In conclusion, CPB in paediatric patients causes global decreases of components of the coagulation and fibrinolytic systems, primarily by haemodilution and secondarily by consumption.

Impact of baseline clinical and laboratory features on the risk of thrombosis in children with acute lymphoblastic leukemia: A prospective evaluation

BACKGROUND

Children with acute lymphoblastic leukemia (ALL) have increased risk of thromboembolism (TE). However, the predictors of ALL-associated TE are as yet uncertain.

OBJECTIVE

This exploratory, prospective cohort study evaluated the effects of clinical (age, gender, ALL risk group) and laboratory variables (hematological parameters, ABO blood group, inherited and acquired prothrombotic defects [PDs]) at diagnosis on the development of symptomatic TE (sTE) in children (aged 1 to ≤18) treated on the Dana-Farber Cancer Institute ALL 05-001 study.

PROCEDURES

Samples collected prior to the start of ALL therapy were evaluated for genetic and acquired PDs (proteins C and S, antithrombin, procoagulant factors VIII (FVIII:C), IX, XI and von Willebrand factor antigen levels, gene polymorphisms of factor V G1691A, prothrombin gene G20210A and methylene tetrahydrofolate reductase C677T, anticardiolipin antibodies, fasting lipoprotein(a), and homocysteine).

RESULTS

Of 131 enrolled patients (mean age [range] 6.4 [1-17] years) 70 were male patients and 20 patients (15%) developed sTE. Acquired or inherited PD had no impact on the risk of sTE. Multivariable analyses identified older age (odds ratio [OR] 1.13; 95% confidence interval [CI]: 1.01, 1.26) and non-O blood group (OR 3.64, 95% CI: 1.06, 12.51) as independent predictors for development of sTE. Patients with circulating blasts had higher odds of developing sTE (OR 6.66; 95% CI: 0.82, 53.85).

CONCLUSION

Older age, non-O blood group, and presence of circulating blasts, but not PDs, predicted the risk of sTE during ALL therapy. We recommend evaluation of these novel risk factors in the development of ALL-associated TE. If confirmed, these easily accessible variables at diagnosis can help develop a risk-prediction model for ALL-associated TE.

Activated protein C generation is greatly decreased in plasma from newborns compared to adults in the presence or absence of endothelium

Activated protein C (APC) generation strongly affects sepsis and thrombosis by inhibition of thrombin generation. However, it is unclear if there are age-related differences in effectiveness of protein C (PC). We studied age effects on plasma APC generation ± endothelium. Defibrinated (Ancrod) plasma (from adults or newborns (umbilical cord)) was recalcified with buffer containing tissue factor ± thrombomodulin (TM) on either plastic or endothelium (HUVEC) at 37oC. Timed subsamples of reaction mixture were taken into either heparin-EDTA or FFRCMK-EDTA solutions and analyzed for APC-PC inhibitor (APC-PCI) or APC-α1antitrypsin (APC-α1AT) by ELISAs. Since heparin converts free APC to APC-PCI, the difference in APCPCI measured in heparin-EDTA and FFRCMK-EDTA samples was equal to free active APC. APC-α2macroglobulin (APC-α2M) was measured as remaining chromogenic activity in heparin-EDTA. Free APC, APC-PCI and APC-α1AT were decreased in newborn compared to adult plasma on plastic. However, APC-α2M made up a larger fraction of inhibitor complexes in newborn plasma. On endothelium, significantly more APC, APC-PCI and APC-α1AT were generated in either plasma compared to that on plastic with excess added TM. APC, APC-PCI and APC-α1AT were also reduced and total APC-α2M increased in newborn plasma on HUVEC. Addition of PC to newborn plasma gave APC generation similar to adult plasma. Thus, free APC, APC-PCI and APC-α1AT generation is reduced in newborn compared to adult plasma with or without endothelium, likely due to reduced plasma PC levels. Endothelium enhances APC generation, regardless of plasma type, possibly because of cell surface factors such as TM, phospholipid and endothelial PC receptor.

Binding of heparin to plasma proteins and endothelial surfaces is inhibited by covalent linkage to antithrombin

Unfractionated heparin (UFH) and low molecular weight heparin (LMWH) are used for prophylaxis and treatment of thrombosis. However, UFH has a short plasma half-life and variable anticoagulant response in vivo due to plasma or vessel wall protein binding and LMWH has a decreased ability to inactivate thrombin, the pivotal enzyme in the coagulation cascade. Covalent linkage of antithrombin to heparin gave a complex (ATH) with superior anticoagulant activity compared to UFH and LMWH, and longer intravenous half-life compared to UFH. We found that plasma proteins bound more to UFH than ATH, and least to LMWH. Also, UFH bound significantly more to endothelial cells than ATH, with 100% of UFH and 94% of ATH binding being on the cell surface and the remainder was endocytosed. Competition studies with UFH confirmed that ATH binding was likely through its heparin moiety. These findings suggest that differences in plasma protein and endothelial cell binding may be due to available heparin chain length. Although ATH is polydisperse, the covalently-linked antithrombin may shield a portion of the heparin chain from association with plasma or endothelial cell surface proteins. This model is consistent with ATH’s better bioavailability and more predictable dose response.

Cerebral sinus venous thrombosis during childhood acute lymphoblastic leukemia therapy: Risk factors and management

BACKGROUND

Cerebral sinus venous thrombosis (CSVT) is a rare but serious complication of childhood acute lymphoblastic leukemia (ALL) therapy. No available consensus exists regarding its risk factors and appropriate management due to the rarity of cases.

PROCEDURES

Out of 209 ALL patients aged 1-21 years treated at the Children's Cancer Center of Lebanon between May 2002 and May 2015, 13 developed CSVT during therapy. Patient characteristics, clinical management, and outcomes were studied.

RESULTS

The incidence of CSVT was 6.2% (95% confidence interval [CI]: 3.4-10.4). Using univariate analysis, increased risk of CSVT was observed with age >10 years (odds ratio [OR]: 3.56, 95% CI: 1.13-11.2), T-cell immunophenotype (OR: 4.14, 95% CI: 1.16-14.7), and intermediate/high risk disease (OR: 3.4, 95% CI: 1.03-11.7). The only statistically significant risk factor by multivariate analysis was the treatment as per the intermediate-/high-risk protocol (HR: 15.6, 95% CI: 1.43-171.3). Most cases (77%) occurred in the postinduction phases of treatment while receiving a combination of asparaginase and dexamethasone rather than prednisone. Treatment with low molecular weight heparin (LMWH) for a minimum of 3 months and until significant radiological improvement is observed resulted in 100% survival rate. All but one patient had complete neurological recovery.

CONCLUSIONS

CSVT is an important complication of childhood ALL therapy. Postinduction combined asparaginase and dexamethasone intensive treatment for intermediate-/high-risk patients was the most important risk factor. Treatment with LMWH for a minimum of 3 months, and until asparginase therapy is over, with major radiological improvement seems to be effective and feasible.

Interactions of heparin and a covalently-linked antithrombin-heparin complex with components of the fibrinolytic system

Unfractionated heparin (UFH) is used as an adjunct during thrombolytic therapy. However, its use is associated with limitations, such as the inability to inhibit surface bound coagulation factors. We have developed a covalent conjugate of antithrombin (AT) and heparin (ATH) with superior anticoagulant properties compared with UFH. Advantages of ATH include enhanced inhibition of surface-bound coagulation enzymes and the ability to reduce the overall size and mass of clots in vivo. The interactions of UFH or ATH with the components of the fibrinolytic pathway are not well understood. Our study utilised discontinuous second order rate constant (k2 ) assays to compare the rates of inhibition of free and fibrin-associated plasmin by AT+UFH vs ATH. Additionally, we evaluated the effects of AT+UFH and ATH on plasmin generation in the presence of fibrin. The k2 values for inhibition of plasmin were 5.74 ± 0.28 x 106 M-1 min-1 and 6.39 ± 0.59 x 106 M-1 min-1 for AT+UFH and ATH, respectively. In the presence of fibrin, the k2 values decreased to 1.45 ± 0.10 x 106 M-1 min1 and 3.07 ± 0.19 x 106 M-1 min-1 for AT+UFH and ATH, respectively. Therefore, protection of plasmin by fibrin was observed for both inhibitors; however, ATH demonstrated superior inhibition of fibrin-associated plasmin. Rates of plasmin generation were also decreased by both inhibitors, with ATH causing the greatest reduction (approx. 38-fold). Nonetheless, rates of plasmin inhibition were 2–3 orders of magnitude lower than for thrombin, and in a plasma-based clot lysis assay ATH significantly inhibited clot formation but had little impact on clot lysis. Cumulatively, these data may indicate that, relative to coagulant enzymes, the fibrinolytic system is spared from inhibition by both AT+UFH and ATH, limiting reduction in fibrinolytic potential during anticoagulant therapy.

Covalently linking heparin to antithrombin enhances prothrombinase inhibition on activated platelets

Factor (F)Xa within the prothrombinase complex is protected from inhibition by unfractionated heparin (UFH), enoxaparin and fondaparinux. We have developed a covalent antithrombin-heparin complex (ATH) with enhanced anticoagulant activity. We have also demonstrated that ATH is superior at inhibiting coagulation factors when assembled on artificial surfaces. The objective of the present study is to determine the ability of ATH vs AT+UFH to inhibit FXa within the prothrombinase complex when the enzyme complex is assembled on the more native platelet system. Discontinuous inhibition assays were performed to determine final k 2-values for inhibition of FXa, FXa within the platelet-prothrombinase, or FXa within prothrombinase devoid of various components. Thrombin generation and plasma clotting was also assayed in the presence of resting/activated platelets ± inhibitors. Protection of FXa was not observed for ATH, whereas a moderate 60% protection was observed for AT+UFH. ATH inhibited platelet-prothrombinase ∼4-fold faster than AT+UFH. Relative to intact prothrombinase, rates for FXa inhibition by AT+UFH in prothrombinase complexes devoid of either prothrombin (II)/activated platelets/FVa were higher. However, inhibition by AT+UFH of prothrombinase devoid of FII yielded slightly lower rates compared to free FXa inhibition. Thrombin generation and plasma clotting was enhanced with activated platelets, while inhibition was better by ATH compared to AT+UFH, thus suggesting an overall enhanced anticoagulant activity of ATH against platelet-bound prothrombinase complexes.

Colorectal cancer with Synchronous liver-limited Metastases: the protocol of an Inception Cohort study (CoSMIC)

INTRODUCTION

Colorectal cancer is the fourth most common cancer in the UK and an important cause of cancer-related death. In 20% of patients, there is metastasis to the liver or beyond at the time of diagnosis. The management of synchronous disease is complex. Conventional surgery removes the colorectal primary first, followed by chemotherapy, with resection of liver metastases as a final step. Advances in the availability and safety of liver surgery, anaesthesia and critical care have made two alternative options feasible. The first is synchronous resection of the primary and liver metastases. The second is resection of the metastatic disease as the first step, termed the reverse or liver-first approach. Currently, evidence is inadequate to inform the selection of care pathway for patients with colorectal cancer and synchronous liver-limited metastases. Specifically, optimal pathways are not defined and there is a dearth of prospectively recorded cohort-defining factors influencing treatment selection or outcome.

METHODS AND ANALYSIS

Colorectal cancer with Synchronous liver-limited Metastases: an Inception Cohort (CoSMIC) is an inception cohort study of patients with a new diagnosis of colorectal cancer with synchronous liver-limited metastases. The sequence of treatment received, and factors influencing treatment decisions, will be evaluated against European Society of Medical Oncology guidelines. Clinical data will be collected, and quality of life, morbidity, mortality and long-term outcome compared for different treatment sequences adjusted for prognostic factors. Disease-free survival or progression will be measured at 1, 2 and 5 years. A nested qualitative study will ascertain patient experiences and clinician perspectives on delivery of care.

ETHICS AND DISSEMINATION

The full study protocol was independently peer reviewed by Professor Kees de Jong (University of Maastricht, Holland). CoSMIC has ethical approval from the National Health Service Research Ethics Committee (14/NW/1397). Results will be disseminated to healthcare professionals and patient groups, and may be used to design a definitive trial addressing areas of equipoise in treatment pathways, as well as optimising current pathways to improve outcomes and experiences.

TRIAL REGISTRATION NUMBER

NCT02456285, pre-results.

Epidemiology and Outcomes of Arterial Ischemic Stroke in Children: The Canadian Pediatric Ischemic Stroke Registry

BACKGROUND

Pediatric arterial ischemic stroke remains incompletely understood. Population-based epidemiological data inform clinical trial design but are scant in this condition. We aimed to determine age-specific epidemiological characteristics of arterial ischemic stroke in neonates (birth to 28 days) and older children (29 days to 18 years).

METHODS

We conducted a 16-year, prospective, national population-based study, the Canadian Pediatric Ischemic Stroke Registry, across all 16 Canadian acute care children's hospitals. We prospectively enrolled children with arterial ischemic stroke from January 1992 to December 2001 and documented disease incidence, presentations, risk factors, and treatments. Study outcomes were assessed throughout 2008, including abnormal clinical outcomes (stroke-related death or neurological deficit) and recurrent arterial ischemic stroke or transient ischemic attack.

RESULTS

Among 1129 children enrolled with arterial ischemic stroke, stroke incidence was 1.72/100,000/year, (neonates 10.2/100,000 live births). Detailed clinical and radiological information were available for 933 children (232 neonates and 701 older children, 55% male). The predominant clinical presentations were seizures in neonates (88%), focal deficits in older children (77%), and diffuse neurological signs (54%) in both. Among neonates, 44% had no discernible risk factors. In older children, arteriopathy (49% of patients with vascular imaging), cardiac disorders (28%), and prothrombotic disorders (35% of patients tested) predominated. Antithrombotic treatment increased during the study period (P < 0.001). Stroke-specific mortality was 5%. Outcomes included neurological deficits in 60% of neonates and 70% of older children. Among neonates, deficits emerged during follow-up in 39%. Overall, an initially decreased level of consciousness, a nonspecific systemic presentation, and the presence of stroke risk factors predicted abnormal outcomes. For neonates, predictors were decreased level of consciousness, nonspecific systemic presentation, and basal ganglia infarcts. For older children, predictors were initial seizures, nonspecific systemic presentation, risk factors, and lack of antithrombotic treatment. Recurrent arterial ischemic stroke or transient ischemic attack developed in 12% of older children and was predicted by arteriopathy, presentation without seizures, and lack of antithrombotic treatment. Emerging deficit was predicted by neonatal age at stroke and by cardiac disease.

CONCLUSIONS

This national data set provides a population-based disease incidence rate and demonstrates the protective effect of antithrombotic treatment in older children, and frequent long-term emerging deficits in neonates and in children with cardiac disorders. Further clinical trials are required to develop effective age-appropriate treatments for children with acute arterial ischemic stroke.

Effect of a structured diabetes education programme in primary care on hospitalizations and emergency department visits among people with Type 2 diabetes mellitus: results from the Patient Empowerment Programme

AIM

To assess whether a structured diabetes education programme, the Patient Empowerment Programme, was associated with a lower rate of all-cause hospitalization and emergency department visits in a population-based cohort of patients with Type 2 diabetes mellitus in primary care.

METHODS

A cohort of 24 250 patients was evaluated using a linked administrative database during 2009-2013. We selected 12 125 patients with Type 2 diabetes who had at least one Patient Empowerment Programme session attendance. Patients who did not participate in the Patient Empowerment Programme were matched one-to-one with patients who did, using the propensity score method. Hospitalization events and emergency department visits were the events of interest. Cox proportional hazard and negative binomial regressions were performed to estimate the hazard ratios for the initial event, and incidence rate ratios for the number of events.

RESULTS

During a median 30.5 months of follow-up, participants in the Patient Empowerment Programme had a lower incidence of an initial hospitalization event (22.1 vs 25.2%; hazard ratio 0.879; P < 0.001) and emergency department visit (40.5 vs 44%; hazard ratio 0.901; P < 0.001) than those who did not participate in the Patient Empowerment Programme. Participation in the Patient Empowerment Programme was associated with a significantly lower number of emergency department visits (incidence rate ratio 0.903; P < 0.001): 40.4 visits per 100 patients annually in those who did not participate in the Patient Empowerment Programme vs. 36.2 per 100 patients annually in those who did. There were significantly fewer hospitalization episodes (incidence rate ratio 0.854; P < 0.001): 20.0 hospitalizations per 100 patients annually in those who did not participate in the Patient Empowerment Programme vs. 16.9 hospitalizations per 100 patients annually in those who did.

CONCLUSIONS

Among patients with Type 2 diabetes, the Patient Empowerment Programme was shown to be effective in delaying the initial hospitalization event and in reducing their frequency.