Home INR monitoring of oral anticoagulant therapy in children using the CoaguChek™ S point-of-care monitor and a robust education program

Guiding warfarin self-management in children: development of a warfarin nomogram

Background

Warfarin therapy in children is impacted by many variables. To support the implementation of a self-management program within a pediatric anticoagulation service, a pediatric-specific warfarin nomogram was needed. A literature review revealed no published pediatric nomograms; therefore, a nomogram was developed drawing upon an evidence-based "Warfarin Information for Clinicians" hospital guideline.

Objectives

This study aimed to evaluate the suitability of a pediatric warfarin nomogram.

Methods

A retrospective audit of electronic medical records compared the dosing and international normalized ratio (INR) retest decisions made by hematology clinicians to the dosing and retesting recommended by a new warfarin nomogram at a pediatric hospital. Children (aged 6 months-18 years) receiving warfarin therapy for >6 months were included. Data were collected between September 2019 and February 2020. Descriptive data analysis was performed. The study was approved by the hospital's Human Research Ethics Committee.

Results

Warfarin dosing and INR retest decisions for 39 children were included, equating to 521 INRs. The nomogram matched 81.4% of clinicians dosing decisions and 30% of INR retest decisions. Moreover, 59% of the clinician-recommended retest dates were earlier than the nomogram recommendation. In the INR 2.0-3.0 group, 84.4% of dosing decisions and 72% of retest decisions matched the nomogram.

Conclusions

These results suggest that this pediatric nomogram is a suitable tool for warfarin dosing, as recommended warfarin doses matched the majority of clinicians' decisions. Modification may be needed to nomogram recommendations for the time to retest. This nomogram can be used to support warfarin self-management and may assist clinicians and patients or families in making evidence-based dosing decisions.

French National Diagnostic and Care Protocol for antiphospholipid syndrome in adults and children

Antiphospholipid syndrome (APS) is a chronic autoimmune disease involving vascular thrombosis and/or obstetric morbidity and persistent antibodies to phospholipids or certain phospholipid-associated proteins. It is a rare condition in adults and even rarer in children. The diagnosis of APS can be facilitated by the use of classification criteria based on a combination of clinical and biological features. APS may be rapidly progressive with multiple, often synchronous thromboses, resulting in life-threatening multiple organ failure. This form is known as "catastrophic antiphospholipid syndrome" (CAPS). It may be primary or associated with systemic lupus erythematosus (associated APS) and in very rare cases with other systemic autoimmune diseases. General practitioners and paediatricians may encounter APS in patients with one or more vascular thromboses. Because APS is so rare and difficult to diagnosis (risk of overdiagnosis) any suspected case should be confirmed rapidly and sometimes urgently by an APS specialist. First-line treatment of thrombotic events in APS includes heparin followed by long-term anticoagulation with a VKA, usually warfarin. Except in the specific case of stroke, anticoagulants should be started as early as possible. Any temporary discontinuation of anticoagulants is associated with a high risk of thrombosis in APS. A reference/competence centre specialised in autoimmune diseases must be urgently consulted for the therapeutic management of CAPS.

A regional anticoagulation program improves safety and outcomes for both children and adults

BACKGROUND

Evidence-based anticoagulation programs usually serve a local, adult patient population. Here we report outcomes for a regional combined pediatric-adult program.

AIMS

The aims of this study were: (1) Compare the pre- vs. post-implementation quality of therapy (% time in therapeutic range (%TTR) and compliance). (2) Assess anticoagulant-relevant outcomes (bleeding and thrombotic complications).

METHODS

Data were collected for the years 2014-2019. Rosendaal linear interpolation was used to calculate %TTR. Bleeding complications were categorized using ISTH-SSC standard nomenclature and new thrombotic events were reviewed.

RESULTS

The patients were divided into a long-term warfarin group (N = 308), 80.2% of whom had cardiac-related therapeutic indications (median age 24y), and a second group (N = 114) comprised of short-term and non-warfarin long-term anticoagulation (median age 16y). Median %TTR for those on long-term warfarin was 78.9%. The incidence of major and clinically relevant non-major bleeding events was 1.65 and 2.43 /100 person-years of warfarin use, respectively. Thromboembolism (TE) incidence was 0.78/100 patient-years of warfarin use. Neither bleeding nor thrombosis was associated with %TTR (p = 0.48). Anticoagulant indication was the only variable associated with bleeding risk (p = 0.005). The second group had no on-therapy TE events but 7.9% experienced bleeding. Complete data were available for a randomly sampled pre-program warfarin group (N = 26). Median %TTR improved from 17.5 to 87% pre- vs. post-implementation. Similarly, compliance (defined as ≥ 1 INR/month) improved by 34.3%.

CONCLUSIONS

In conclusion, this program significantly improved and sustained %TTR and compliance. The lack of association between bleeding and thrombosis events and %TTR may be related to the high median %TTR (> 70%) achieved by this approach.

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

Background

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

Objectives

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

Methods

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

Results

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

Conclusion

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

Edoxaban for Thromboembolism Prevention in Pediatric Patients With Cardiac Disease

BACKGROUND

Standard of care (SOC) anticoagulation for thromboembolism (TE) prevention in children with cardiac disease includes low molecular weight heparins or vitamin K antagonists. Limited data exists for alternate use of direct oral anticoagulants in children.

OBJECTIVES

The investigators aimed to obtain safety and efficacy data for edoxaban in children.

METHODS

We performed a phase 3, multinational, prospective, randomized, open-label, blinded-endpoint trial in patients <18 years of age with cardiac disease (ENNOBLE-ATE [Edoxaban for Prevention of Blood Vessels Being Blocked by Clots (Thrombotic Events) in Children at Risk Because of Cardiac Disease] trial). Patients were randomized 2:1 to age- and weight-based oral edoxaban once daily vs SOC for 3 months (main study period), stratified by cardiac diagnosis. Both groups could continue in an open-label edoxaban extension arm through 1 year. The primary endpoint was adjudicated clinically relevant bleeding (CRB). The main secondary endpoint was symptomatic TE or asymptomatic intracardiac thrombosis.

RESULTS

The modified intention-to-treat cohort included 167 children. One patient per group experienced a nonmajor CRB in the main period. Treatment-emergent adverse events occurred in 46.8% (51 of 109) with edoxaban and 41.4% (24 of 58) with SOC. One SOC patient experienced 2 TE events (DVT with PE). Among 147 children in the extension, 1 CRB event (0.7%) and 4 TEs occurred (2.8%; 2 strokes and 2 of 33 Kawasaki disease patients with coronary artery thromboses and/or myocardial infarctions).

CONCLUSIONS

Edoxaban is a potential alternative mode of thromboprophylaxis in children with cardiac disease showing low rates of CRB and TEs with advantages of once daily dosing and infrequent monitoring requirement. (ENNOBLE-ATE [Edoxaban for Prevention of Blood Vessels Being Blocked by Clots] (Thrombotic Events) in Children at Risk Because of Cardiac Disease trial; NCT03395639).

ENNOBLE-ATE trial: an open-label, randomised, multi-centre, observational study of edoxaban for children with cardiac diseases at risk of thromboembolism

Children with cardiac diseases suffer from significant morbidity and mortality secondary to thromboembolic complications. Anticoagulant agents currently used for thromboprophylaxis have many limitations, including subcutaneous administration (low molecular weight heparins) and requirement for frequent monitoring via venipuncture (vitamin K antagonists). Edoxaban is an oral direct factor Xa inhibitor without need of monitoring. In the treatment of venous thromboembolism in adults, edoxaban has shown to be effective and safe.This manuscript summarises the rationale and design of a phase 3, open-label, randomised controlled trial to evaluate and compare the safety and efficacy of edoxaban against standard of care (namely, vitamin K antagonist and low molecular weight heparin) in children with cardiac diseases.A goal of 150 children with cardiac diseases at risk of thromboembolic complications who need primary or secondary anticoagulant prophylaxis will be recruited. Eligible children between 6 months and <18 years of age will be randomised in a ratio of 2 to 1 for edoxaban versus standard of care. Randomisation will be stratified based on underlying cardiac disease and concomitant use of aspirin for patients other than Kawasaki disease. The primary outcome will be safety, comprised of major and clinically relevant non-major bleeding in first 3 months of treatment. Bleeding beyond 3 months, symptomatic and asymptomatic thromboembolic events, and pharmacokinetic and pharmacodynamic parameters will be evaluated as secondary outcomes.Randomised controlled anticoagulation trials are challenging in children. This study will evaluate a potentially valuable alternative of oral anticoagulant prophylactic use in children with cardiac diseases.

Home point-of-care international normalised ratio monitoring sustained by a non-selective educational program in children

Adverse events related to vitamin K antagonist (VKA) therapy might be reduced by point-of-care international normalised ratio (POC INR) monitoring supported by an education program (EP). Our aim was to evaluate the efficacy of a non-selective VKA paediatric EP (regardless of the social, economic, educational or linguistic levels) by analysing the time spent in the therapeutic range (TTR), VKA adverse events and compliance to treatment, and INR control prescriptions. The EP was modified from the pediatric EP previously described but improved by a specifically devised child-focused game. One hundred four consecutive children (median age 8 years) receiving VKA were included in a standardised E P. Patients were in self-testing, and dose adjustments were made by a single physician for three tolerance ranges according to the underlying disease: [2.5–4], [1.8–3.2], and [1.5–2.5]. The median follow-up was 481 days [70–1,001]. The overall TTR was 81.4% [36–100]. The TTR were 74%, 85.6% and 89% for the ranges [2.5–4], [1.8–3.2], and [1.5–2.5], respectively. These results were sustainable during the study period. Only one serious VKA adverse event was recorded. The median number of POC INR tests was 2.5 [1.6–5.7] INR per patient and month. Patients/families performed POC INR when requested in 86.9% of the cases. More than 90% of the families found the EP supportive and wished to follow a long-term reinforcement program. In conclusion, this non-selective child-focused EP for VKA therapy, strongly supported by our dedicated game, is useful in maintaining efficacy, safety and compliance to anticoagulation and its monitoring.

Self-testing and self-management of oral anticoagulation therapy in children

Children and adolescents on oral anticoagulation therapy (OAT) present special challenges in terms of rapid fluctuations in International Normalised Ratio (INR) values, interruption in daily life due to frequent hospital/doctor visits, and difficulties and pain in the performance of venepuncture. Optimised management of OAT improves the quality of treatment, potentially accomplished by new methods such as patient self-testing (PST) and patient self-management (PSM). A review was performed, identifying 11 trials with children and adolescents. All studies had different methodological problems, predominantly by being non-randomised trials. A total of 284 patients were included with a mean follow-up of 22 months, finding a time within therapeutic INR target range between 63% and 84%. The coagulometers used for estimating the INR values were found to have sufficient precision and accuracy for clinical use, but external quality control is probably advisable. It can be concluded that PST and PSM are at least as good treatment options as conventional management in highly selected children. Larger studies, preferably randomised, controlled trials using clinical endpoints, are obviously needed in order to elucidate whether these new regimens of treatment are superior to conventional management of oral anticoagulation therapy.

Quality of life in children participating in a non-selective INR self-monitoring VKA-education programme

BACKGROUND

The quality of life (QoL) of children receiving vitamin K antagonist (VKA) treatment has been scarcely studied.

AIM

To assess QoL of children, and its evolution, throughout our non-selective international normalized ratio (INR) self-monitoring education programme.

METHODS

Children and parents completed QoL questionnaires (Qualin, PedsQL) during education sessions. Scores were compared with those from controls.

RESULTS

A total of 111 children (mean±standard deviation age 8.7±5.4 years) were included over a 3-year period. Indications for VKA treatment were congenital heart diseases (valve replacement [42.3%], total cavopulmonary connection [29.7%]), myocardiopathy (11.7%), coronary aneurysm (7.2%), venous/intracardiac thrombosis (4.5%), pulmonary artery hypertension (1.8%), arrhythmia (0.9%) and extra-cardiac disease (1.8%). Eighty children, 105 mothers and 74 fathers completed the QoL questionnaires. QoL was good among children aged 1-4 years and moderately impaired in those aged between 5 and 18 years. There was no significant relationship between self-reported QoL and patient's sex, type of VKA, number of group sessions attended, disease duration or time of diagnosis (prenatal or postnatal). QoL scores were significantly lower among children with congenital heart diseases compared with other diseases. There were few differences in QoL between children under transient VKA treatment and those treated for life. Parental proxy QoL scoring correlated well with but was significantly lower than child self-assessments. QoL reported by mothers increased throughout the education programme, independently of any improvement of the health condition.

CONCLUSIONS

This QoL study provides original data from a large cohort of children and their parents participating in a formalized INR self-monitoring education programme for VKA treatment.

Clinical evaluation of whole blood prothrombin time (PT) and international normalized ratio (INR) using a Laser Speckle Rheology sensor

Prothrombin time (PT) and the associated international normalized ratio (INR) are routinely tested to assess the risk of bleeding or thrombosis and to monitor response to anticoagulant therapy in patients. To measure PT/INR, conventional coagulation testing (CCT) is performed, which is time-consuming and requires the separation of cellular components from whole blood. Here, we report on a portable and battery-operated optical sensor that can rapidly quantify PT/INR within seconds by measuring alterations in the viscoelastic properties of a drop of whole blood following activation of coagulation with thromboplastin. In this study, PT/INR values were measured in 60 patients using the optical sensor and compared with the corresponding CCT values. Our results report a close correlation and high concordance between PT/INR measured using the two approaches. These findings confirm the accuracy of our optical sensing approach for rapid PT/INR testing in whole blood and highlight the potential for use at the point-of-care or for patient self-testing.

International normalized ratio self-testing and self-management: improving patient outcomes

Long term oral anti-coagulation with vitamin K antagonists is a risk factor of hemorrhagic or thromebomlic complications. Periodic laboratory testing of international normalized ratio (INR) and a subsequent dose adjustment are therefore mandatory. The use of home testing devices to measure INR has been suggested as a potential way to improve the comfort and compliance of the patients and their families, the frequency of monitoring and, finally, the management and safety of long-term oral anticoagulation. In pediatric patients, increased doses to obtain and maintain the therapeutic target INR, more frequent adjustments and INR testing, multiple medication, inconstant nutritional intake, difficult venepunctures, and the need to go to the laboratory for testing (interruption of school and parents’ work attendance) highlight those difficulties. After reviewing the most relevant published studies of self-testing and self-management of INR for adult patients and children on oral anticoagulation, it seems that these are valuable and effective strategies of INR control. Despite an unclear relationship between INR control and clinical effects, these self-strategies provide a better control of the anticoagulant effect, improve patients and their family quality of life, and are an appealing solution in term of cost-effectiveness. Structured education and knowledge evaluation by trained health care professionals is required for children, to be able to adjust their dose treatment safely and accurately. However, further data are necessary in order to best define those patients who might better benefit from this multidisciplinary approach.

Safety and Efficacy Outcomes of Home and Hospital Warfarin Management Within a Pediatric Anticoagulation Clinic

The complexity of managing children with chronic disease has led to an increase in the use of long-term warfarin therapy. Time in therapeutic range (TTR) is the preferred method for determining efficacy and stability of warfarin management. This study aimed to determine the TTR achievement and incidence of adverse events among pediatric warfarin patients managed by an anticoagulation clinic over 12 months and to compare TTR achievement between patients self-testing (PST) at home and those monitored using routine methods. International normalized ratio (INR) results reported for 2012 for children currently having their warfarin therapy managed by a dedicated pediatric anticoagulation clinic were analyzed. Warfarin-related adverse events were recorded. A total of 164 patients were included. In total, 93 children performed PST and 71 children tested their INR at a hospital or pathology service. TTR achievement for the cohort was 67.1% (95% confidence interval, 64.4-69.7). A total of 69.2% of INR tests conducted at home were within the TTR compared with 64.3% of INR tests conducted at a hospital or pathology service (P=0.07). One major bleeding event occurred and there was 1 thrombotic episode. PST demonstrated noninferior warfarin stability compared with routine methods. Routine outcome evaluation of pediatric anticoagulation management within single institutions is necessary to confirm the success of such programs.

An Education Program for Patient Self-Management of Warfarin

INTRODUCTION

Although improved anticoagulation therapy outcomes have been demonstrated in clinical trials evaluating warfarin patient self-management (PSM) programs, these studies did not provide detailed information regarding PSM program development and patient training.

OBJECTIVE

To evaluate the feasibility of and methods for developing and administering an education program to support a novel pilot warfarin PSM program.

METHODS

Patients receiving warfarin for atrial fibrillation were recruited to participate in a prospective, intervention-only, open-label pilot PSM program that released venipuncture international normalized ratio results to patients via a secure, online Web site. To support the pilot, a warfarin PSM education program with a dosing algorithm was developed and delivered to patients during a two-hour classroom session.

MAIN OUTCOME MEASURE

A comparison of participants' PSM competency test scores before and after attending the PSM program.

RESULTS

Forty-four patients attended the education program. The mean age of participants was 71 years and 50% were women. Patients declining study participation were older (p = 0.003) and had a greater burden of chronic disease (p = 0.005) than participants. Following PSM training, the mean competency score improved from 55.8% to 88.8% (p < 0.001), and the proportion achieving a passing score increased from 34.9% to 95.3% (p < 0.001). In the poststudy survey, 100% of responders perceived that PSM training prepared them to self-manage warfarin, and 92.9% of responders were comfortable changing warfarin doses on their own.

CONCLUSION

Developing and administering a warfarin PSM education program for patients with atrial fibrillation was feasible. Improvement in PSM competency and high levels of self-reported comfort with warfarin PSM were identified.

EMPoWARed: Edmonton pediatric warfarin self-management study

BACKGROUND

Patient self-management (PSM) in adults is safer and more cost effective than conventional management. Warfarin is a narrow therapeutic index drug with individual patient response to changes and frequently a long-term therapy. Children and their families are proposed to be able to effectively manage their child's warfarin therapy. Increased health related quality of life is highly associated with effective therapy in patients with chronic conditions.

OBJECTIVES

The aim of this study is to evaluate the safety and efficacy of PSM over time including HRQOL and variables that may influence PFU success at PSM.

PATIENTS/METHODS

Children and their family units (PFUs) current performing patient self-testing/monitoring for ≥ 3 months were enrolled in this cohort study. PFUs participated in comprehensive education on warfarin testing and management followed by an apprenticeship. Socio-demographic, clinical, and laboratory data were collected to evaluate safety and efficacy and health related quality of life. Outcomes were compared between the first 6 months on PSM (phase 1) and the last 6 months data collected on PSM (phase 2).

RESULTS

Forty-two patients performed PSM for a median of 2.7 years (range: 1.1-6.2 years). Time in therapeutic range was 90% and 92.9% (p=0.30) in phases 1 and 2 respectively. All measures were strongly associated with improved heath related quality of life. PFUs socio-demographic status did not influence success at PSM. All PFUs maintained warfarin knowledge and INR testing competency. Warfarin dosing decision errors median 0 (range: 0-5, p=0.73) and a median 0 (range 0-4, p=0.55) per patient in phases 1 and 2 respectively. There were no adverse hemorrhagic or thrombotic events.

CONCLUSIONS

Empowering PFUs to self-manage warfarin results in increased knowledge and understanding of their health condition, improved commitment to their health care and adherence to medication regimens and is demonstrated to be sustainable over time.

The economic costs of routine INR monitoring in infants and children--examining point-of-care devices used within the home setting compared to traditional anticoagulation clinic monitoring

INTRODUCTION

The use of point-of-care (POC) devices within the home for routine INR monitoring has demonstrated reliability, safety and effectiveness in the management of infants and children requiring long-term warfarin therapy. However, a comprehensive cost-analysis of using this method of management, compared to attending anticoagulation clinics has not been reported. The aim of this study was to compare the estimated societal costs of attending anticoagulation clinics for routine INR monitoring to using a POC test in the home.

MATERIALS AND METHODS

This study used a comparative before-and-after design that included 60 infants and children managed via the Haematology department at a tertiary paediatric centre. Each participant was exposed to both modes of management at various times for a period of ≥3 months. A questionnaire, consisting of 25 questions was sent to families to complete and return. Data collected included: the frequency of monitoring, mode of travel to and from clinics, total time consumed, and primary carer's income level.

RESULTS

The home monitoring cohort saved a total of 1 hour 19 minutes per INR test compared to attending anticoagulation clinics and had a cost saving to society of $66.83 (AUD) per INR test compared to traditional care; incorporating health sector costs, travel expenses and lost time.

CONCLUSIONS

The traditional model of care requires a considerable investment of time per test from both child and carer. Home INR monitoring in infants and children provides greater societal economic benefits compared to traditional models.

Quality of life assessment in children commencing home INR self-testing

INTRODUCTION

Management of oral anticoagulant therapy (OAT) in children is complex and frequent testing of the International Normalised Ratio (INR) is a significant burden. This study evaluates the impact of a home INR self-testing (home ST) program on the quality of life (QoL) of children and their families. The aim of the study was to determine if participation in a home ST program improves QoL for children requiring long-term OAT and their families.

MATERIALS AND METHODS

Children aged eight to 18 years requiring long-term OAT and parents of children participated. Quantitative methods comprised three validated QoL questionnaires; the anticoagulation specific PAC QL©, the PedsQL™ and the PedsQL FIM™. Questionnaires were completed before commencing home ST and 6-12 months later. Qualitative methods consisted of open-ended questions which participants answered when completing the questionnaires for the second time. Results of INRs tested at home were collected.

RESULTS

Fifty-five parents and 35 children participated. The percentage of time the children's INRs were in their target therapeutic range was 71.3. Parents reported statistically significant improvements in QoL for themselves (mean increase 6.9), their family (mean increase 8.6) and their child (mean increase 11.1) following the commencement of home ST (difference p≤0.003 on all questionnaires). The children did not report a statically significant improvement in QoL.

CONCLUSION

Parents reported significant improvement for their child's QoL, their QoL and the families' function following commencement of home ST. Children did not report a significant improvement in their QoL, but clearly identified satisfaction with home ST.

Successful treatment of acute lymphoblastic leukemia in a child with trisomy 21 and complex congenital heart disease with mechanical prosthetic valve

A 10-year-old girl with trisomy 21 and complex congenital heart disease presented with acute lymphoblastic leukemia. Her chemotherapy required modifications due to poor baseline cardiac status and a mechanical prosthetic heart valve that was dependent on anticoagulation. We describe our management including the use of low-molecular-weight heparin as anticoagulation for a mechanical heart valve, the safe delivery of intrathecal chemotherapy included bridging with unfractionated heparin, and the use of fluoroscopic guidance to minimize the risk of bleeding. Adjustments were made to avoid anthracyclines. The child tolerated therapy well without complications and remains relapse free five years after diagnosis.

The in vitro anticoagulant effect of rivaroxaban in children

INTRODUCTION

Current anticoagulation therapy in children is less than ideal, requiring regular venous monitoring and dosing adjustments. Limitations associated with conventional anticoagulants have prompted the development of novel drugs that specifically target key proteins in the coagulation system. Rivaroxaban is the first oral, direct Factor Xa inhibitor available for the prevention of venous thromboembolism in adults. Its predictable pharmacokinetic profile, high oral bioavailability and once-daily dosing make rivaroxaban an optimal anticoagulant that warrants investigation in children. The aim of this study was to investigate the age-related anticoagulant effect of rivaroxaban in vitro.

MATERIALS AND METHODS

Age-specific plasma pools were created (i.e. 28 days-23 months, 2-6, 7-11, 12-16 years and adults) and spiked with increasing concentrations of rivaroxaban (0-500 ng/ml). Commercially available PT, APTT and anti-Factor Xa assays, as well as sub-sampling thrombin generation assays, were used to measure rivaroxaban effect.

RESULTS

The results of this study indicate that there are no significant differences in rivaroxaban effect across the age groups in vitro.

CONCLUSION

In vivo studies are required to confirm the consistency of dose-response across the paediatric age groups.

Natural Health Product Utilization in Warfarinized Children; Prevalence and Knowledge

Background:

The need for long-term thromboprophylaxis in children using warfarin therapy is increasing. Natural health products (NHPs) are administered to children by parents who perceive them to be useful and acceptable adjuncts or alternatives to conventional therapies. Interactions of NHPs with prescribed therapies may result in serious adverse events. NHP usage is underevaluated in children and there are no studies evaluating NHP usage in warfarinized children.

Objectives:

To explore NHP use in warfarinized children and their siblings to determine the prevalence, varieties, and reasons for NHP usage, as well as the potential effect on warfarinization (eg, time in therapeutic range [TTR]).

Methods:

This is a 3-phase cross-sectional cohort study that includes the (1) prevalence (2) NHP education and knowledge assessment, and (3) the follow-up NHP utilization phase.

Results:

Forty-six percent of warfarinized children consumed NHPs, with time in therapeutic range of 74%. The mean score for baseline knowledge of NHPs and warfarin following the education phase was 67%. Follow-up NHP use was 30%, and increased consistency of utilization with TTR was 83% (p < 0.05), consistent with education provided.

Conclusions:

The consistent prevalence rates over time of NHP usage in warfarinized children indicate the need for future studies. Education remains vital to combat the potential risks of NHP-warfarin interaction, encouraging patient disclosure and consistency.

Antithrombotic therapy in neonates and children: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

BACKGROUND

Neonates and children differ from adults in physiology, pharmacologic responses to drugs, epidemiology, and long-term consequences of thrombosis. This guideline addresses optimal strategies for the management of thrombosis in neonates and children.

METHODS

The methods of this guideline follow those described in the Methodology for the Development of Antithrombotic Therapy and Prevention of Thrombosis Guidelines: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines.

RESULTS

We suggest that where possible, pediatric hematologists with experience in thromboembolism manage pediatric patients with thromboembolism (Grade 2C). When this is not possible, we suggest a combination of a neonatologist/pediatrician and adult hematologist supported by consultation with an experienced pediatric hematologist (Grade 2C). We suggest that therapeutic unfractionated heparin in children is titrated to achieve a target anti-Xa range of 0.35 to 0.7 units/mL or an activated partial thromboplastin time range that correlates to this anti-Xa range or to a protamine titration range of 0.2 to 0.4 units/mL (Grade 2C). For neonates and children receiving either daily or bid therapeutic low-molecular-weight heparin, we suggest that the drug be monitored to a target range of 0.5 to 1.0 units/mL in a sample taken 4 to 6 h after subcutaneous injection or, alternatively, 0.5 to 0.8 units/mL in a sample taken 2 to 6 h after subcutaneous injection (Grade 2C).

CONCLUSIONS

The evidence supporting most recommendations for antithrombotic therapy in neonates and children remains weak. Studies addressing appropriate drug target ranges and monitoring requirements are urgently required in addition to site- and clinical situation-specific thrombosis management strategies.

Anticoagulation therapy: indications, monitoring, and complications

Anticoagulation for thromboembolic disease and bleeding, the main complication of anticoagulation therapy, are uncommon but are potentially life- or limb-threatening conditions that may present in the pediatric emergency department. Thromboembolic disease in children usually occurs as a complication of vascular access, primarily in children with congenital heart disease or cancer. However, complications of anticoagulation therapy used in the treatment of venous thromboembolism, pulmonary embolism, and blocked central venous catheter; arterial thromboembolism, including arterial ischemic stroke, Kawasaki disease, and after cardiac surgery, may warrant a visit to n the pediatric emergency department. Anticoagulation therapy may take the form of unfractionated heparin, low-molecular weight heparin, vitamin K antagonists, acetylsalicylic acid, or thrombolytic therapy. Monitoring anticoagulation therapy in children is very important and follows adult guidelines. Anticoagulant dosing may be adjusted based on activated partial thromboplastin time, anti-factor Xa level, and international normalized ratio.

Aspects of anticoagulation in children

The number of children receiving anticoagulation is increasing. Thromboembolic events are associated with significant risk of morbidity and mortality although the optimal management of asymptomatic events remains unclear. Specific challenges in paediatrics include the diagnosis of thrombosis, delivery and monitoring of anticoagulation in a wide range of ages from neonates through to adolescents. The development of the haemostatic system as children age results in changing pathophysiology of thrombosis and response to anticoagulation agents. Although registry and observational studies have provided vital information, specific paediatric, prospective anticoagulation studies have been few and limited in design. The result is that much of current practice is extrapolated from adult studies. Traditional anticoagulants have significant limitations. Both heparin and warfarin are in widespread use but many fundamental questions regarding dose, therapeutic range, efficacy and optimum duration have not been fully answered. Alternative agents, such as direct thrombin inhibitors and the selective anti-factor Xa inhibitor fondaparinux, may have advantages for children. Clinical trials in adults and preliminary data in children are promising but caution should be applied until specific paediatric studies have demonstrated safety and efficacy.

Evaluating safety, effectiveness, and user satisfaction of home international normalized ratio monitoring service: experience from a tertiary pediatric cardiology unit in the United Kingdom

Home international normalized ratio (INR) monitors are being increasingly used for monitoring the adequacy of anticoagulation in children on long-term warfarin. Their safety and effectiveness in the home setting has not been fully established. The purpose of this study was to explore the safety and effectiveness of home INR monitoring service in managing anticoagulation in children with congenital heart disease. At the Pediatric Cardiology Regional Referral Center, we studied records of 41 children on warfarin and assessed the control of anticoagulation and frequency of adverse reactions over a 1-year period. User satisfaction was assessed by means of telephone interviews. The study found that the therapeutic INR range was maintained for over 57% of the total study period. There were no reported instances of major or minor hemorrhages. On six occasions, subtherapeutic INR levels necessitated hospitalization for heparinization. Mitral valve replacement was significantly associated with poor control (p < 0.05). User satisfaction was high for all aspects of the service evaluated. The hospital-assisted home INR monitoring service is a safe and effective means of managing anticoagulation in children. In addition, it ensures good compliance and a high level of user satisfaction.

KIDCLOT: the importance of validated educational intervention for optimal long term warfarin management in children

BACKGROUND

Advances in medical and surgical therapy in children have resulted in increased survival in children with primary illnesses. However, thrombosis is a serious complication of this success and results in mortality and morbidity. Prevention or treatment of thrombosis using warfarin is challenging in children due to its narrow therapeutic index and the unique differences in children, including variable nutritional intake and the occurrence of common concomitant viral or bacterial illnesses which alter warfarin metabolism. The variable response to warfarin in children necessitates frequent International Normalized Ratio (INR) monitoring. Education may improve time in therapeutic range (TTR) a measure of warfarin effect, and a surrogate for patient adherence, safety and efficacy.

METHODS

The Pediatric Anticoagulation program (Stollery Children's Hospital) developed a novel child-focused educational program KIDCLOT-POC about warfarin therapy and POC-INR meter use. A total of twenty eight children, and their caregivers, participated in KIDCLOT-POC. Questionnaire score comparisons and practical demonstrations assessed the learners' theoretical and practical knowledge of warfarin management.

RESULTS

In caregivers, the median pre, post and knowledge retention questionnaire scores were 50 (IQR 27), 93 (IQR 6) (p<0.0001) and 96 (IQR 6) (p<0.0001), respectively. In the 18 children who were >or=6 years of age, post and knowledge retention questionnaire scores were 90 (IQR 16) and 92 (IQR 23) (p=0.44), respectively. The TTR for all children was 81.7% (SD 13.1).

CONCLUSIONS

Implementation of KIDCLOT-POC program appears to promote high knowledge development and retention in children and caregivers and high TTR with no adverse events.

Antithrombotic therapy in neonates and children: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition)

This chapter about antithrombotic therapy in neonates and children is part of the Antithrombotic and Thrombolytic Therapy: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition). Grade 1 recommendations are strong and indicate that the benefits do, or do not, outweigh risks, burden, and costs, and Grade 2 suggests that individual patient values may lead to different choices (for a full understanding of the grading, see Guyatt et al in this supplement, pages 123S-131S). In this chapter, many recommendations are based on extrapolation of adult data, and the reader is referred to the appropriate chapters relating to guidelines for adult populations. Within this chapter, the majority of recommendations are separate for neonates and children, reflecting the significant differences in epidemiology of thrombosis and safety and efficacy of therapy in these two populations. Among the key recommendations in this chapter are the following: In children with first episode of venous thromboembolism (VTE), we recommend anticoagulant therapy with either unfractionated heparin (UFH) or low-molecular-weight heparin (LMWH) [Grade 1B]. Dosing of IV UFH should prolong the activated partial thromboplastin time (aPTT) to a range that corresponds to an anti-factor Xa assay (anti-FXa) level of 0.35 to 0.7 U/mL, whereas LMWH should achieve an anti-FXa level of 0.5 to 1.0 U/mL 4 h after an injection for twice-daily dosing. In neonates with first VTE, we suggest either anticoagulation or supportive care with radiologic monitoring and subsequent anticoagulation if extension of the thrombosis occurs during supportive care (Grade 2C). We recommend against the use of routine systemic thromboprophylaxis for children with central venous lines (Grade 1B). For children with cerebral sinovenous thrombosis (CSVT) without significant intracranial hemorrhage (ICH), we recommend anticoagulation initially with UFH, or LMWH and subsequently with LMWH or vitamin K antagonists (VKAs) for a minimum of 3 months (Grade 1B). For children with non-sickle-cell disease-related acute arterial ischemic stroke (AIS), we recommend UFH or LMWH or aspirin (1 to 5 mg/kg/d) as initial therapy until dissection and embolic causes have been excluded (Grade 1B). For neonates with a first AIS, in the absence of a documented ongoing cardioembolic source, we recommend against anticoagulation or aspirin therapy (Grade 1B).

Venous thrombosis in children

The advances in pediatric tertiary care have resulted in a decrease in the mortality of children with serious underlying conditions. Consequently, there has been an increase in previously rare complications of therapy in children, including venous thrombosis. Although there is a paucity of properly designed trials in the field of pediatric thrombosis, many advances have been made over the past 15 years. Venous thrombosis in children has been the subject of many reviews. This review is an update of the available evidence in the management of venous thrombosis in children, excluding thrombosis of the CNS.