Real-world use of apixaban for the treatment and prevention of thrombosis in children with cardiac disease

Myocardial Infarction in Kawasaki Disease

OBJECTIVE

To evaluate the clinical features, diagnostic methods, treatment courses, and outcomes of myocardial infarction (MI) among patients with Kawasaki disease (KD).

STUDY DESIGN

This retrospective, single-center study reviewed patients with a history of KD who experienced MI from 1984 to 2023. Data collection included demographics, clinical presentation, imaging findings, interventions, and outcomes.

RESULTS

Among 22 patients, 86% were male, with a median KD onset of 14 months (range: 3 months-15 years). MI was diagnosed at the time of the event in seven patients, through surveillance magnetic resonance imaging in eight asymptomatic cases, and by other diagnostic tests in four. Nearly half (48%) of MIs occurred within three months of acute KD, and 81% within two years. All patients had at least one large or giant coronary artery aneurysm, most commonly in the proximal left anterior descending artery. Seven patients underwent coronary artery bypass grafting, one had percutaneous coronary intervention, and one was listed for heart transplantation. Two patients died from MI-related complications in the 1980s, and 23% had left ventricular dysfunction on follow-up.

CONCLUSIONS

A high prevalence of missed MI diagnoses and adverse outcomes highlight the need for improved early detection and management. Although MI occurred only in patients with giant aneurysms, additional risk factors remain unclear. Future studies exploring computational modeling and genetic predispositions may help personalize antithrombotic regimens and optimize care for high-risk patients.

Impact of Anticoagulation Therapy After Bioprosthetic and Homograft Pulmonary Valve Replacement

BACKGROUND

The effect of anticoagulation on early postoperative outcomes after pulmonary valve replacement (PVR) with bioprosthetic valves and homografts is not yet defined. We hypothesized that short-term anticoagulation would be associated with improved valve durability.

METHODS

Patients undergoing PVR or right ventricle-to-pulmonary artery conduits with a bioprosthetic or homograft valve >15 mm in diameter between January 2015 and April 2021 at Boston Children's Hospital were retrospectively compared by anticoagulation status. Survival, postoperative echocardiographic data, and the incidence of pulmonary valve reintervention and prosthetic valve dysfunction were compared using multivariable Cox and logistic regression analyses adjusted for a propensity score based on anticoagulation therapy.

RESULTS

Among 531 patients with a median follow-up of 1.16 years, 130 received anticoagulation therapy. Freedom from reintervention was 99%, 92%, and 86% at 1, 3, and 5 years, respectively. Adjusted for propensity score, there was no association between reintervention and anticoagulation (hazard ratio, 0.78; 95% CI, 0.18-3.47; P = .75). The propensity score-adjusted rates of valve dysfunction were 9% in anticoagulated patients and 15% in non-anticoagulated patients (odds ratio, 0.54; 95% CI, 0.18-1.56; P = .25). There was no difference in early major bleeding rates between groups (3.4% vs 2.4%, P = .59) or in other postoperative outcomes. Only 1 of 18 (6%) of all bleeding events in the anticoagulated group occurred after starting anticoagulation.

CONCLUSIONS

Anticoagulation therapy appeared safe with no association with major postoperative bleeding. However, additional follow-up is necessary to assess its impact on midterm to long-term valve durability after PVR.

Anticoagulation with warfarin for paediatric cardiac indications: a retrospective study

Warfarin is used as anticoagulation for children for a wide range of cardiac indications but carries the disadvantage of requiring international normalised ratio monitoring and dose adjustment. Management of warfarin therapy is challenging due to its narrow therapeutic window and is further complicated in children by dietary changes, frequent illnesses, and developing systems of metabolism and haemostasis.A retrospective review was performed of patients' medical records to assess the indication for warfarin use, percentage of international normalised ratio values in target range (%ITR), and frequency of phlebotomy.Twenty-six patients were identified. The most common indication for warfarin use was in patients post-total cavo-pulmonary connection (n = 19, 73%). We demonstrated a variability in duration of warfarin therapy following total cavo-pulmonary connection (median of 11.1 months). Nineteen (73%) patients had used the CoaguChek machine for home measurement of international normalised ratio. The median frequency of phlebotomy for all indications was once every 10 days, and the median %ITR was 55.4 % (29.7-86.4%). Of note, the percentage under target range in the patients with mechanical mitral (n = 2) and aortic valves (n = 1) was found to be 23% and 33%, respectively.These data demonstrate a high frequency of international normalised ratio values outside of the target range as seen in previous studies of warfarin in children. This necessitates frequent phlebotomy and dose changes, which can have a significant effect on the quality of life of these patients and their families highlighting the need to focus on quality improvement in the area of anticoagulation in paediatric cardiac patients.

The Use of DOACs in Pediatrics: Current Therapeutic and Prophylactic Indications, Cardiac Indications, and Real-World Evidence-A Review

Based on clinical trials that have been conducted and published in the past decade, direct oral anticoagulants (DOACs) are increasingly being used as an antithrombotic treatment in children with venous thrombotic events and to prevent thrombotic events in children at risk. In this review, current indications and standards for the initiation of DOACs in children are summarized for the treatment of venous thrombotic events and for the primary and secondary prevention in children at risk of developing thromboses based on the published randomized controlled trials (RCT). Similarly, indications for DOACs in children with underlying cardiac disease are portrayed based on RCT findings. Lastly, available real-world data are reviewed for the use of DOACs in pediatric patients with a focus on patients at higher risk of both thrombosis and bleeding who were primarily excluded from the RCTs. DOACs contribute largely to the evolving individualization of care of thrombotic events in children, but at-risk patient populations remain underrepresented regarding DOAC experience, such as preterm infants, and children with severe renal or hepatic disease. Real-world data from observational studies and registries will continue to be necessary to establish DOACs' effectiveness and safety in children in everyday clinical use.

A review of the perioperative management of direct oral anticoagulants for pediatric anesthesiologists

BACKGROUND

Although direct oral anticoagulants (DOACs) have been used in the adult population for over a decade, DOACs use has begun to rise in pediatric populations since FDA approval of rivaroxaban and dabigatran, DOACs offer several advantages for pediatric patients, to other anticoagulants, including a similar safety profile, minimal lab monitoring, and ease of administration. The rise in DOAC use has led to an increasing number of pediatric patients managed on DOACs presenting for elective and urgent procedures. Perioperative management of anticoagulation is often challenging for providers due to the lack of expert consensus guidelines and the difficulty in balancing a patient's thrombotic risk with bleeding risk for a given procedure.

AIMS

Using the most up to date literature, we provide a focused review on the perioperative management of DOACs in pediatric patients.

CONCLUSIONS

This work presents a focused review for pediatric anesthesiologists on clinically available DOACs, perioperative monitoring and management of DOACs, as well as options and indications for reversal. While consensus expert practice guidelines are still needed, we hope this work will familiarize perioperative physicians with these agents, recommended uses, and potential perioperative management.

Real-World Use and Outcomes of Apixaban for Early Post-Surgical Fontan Thromboprophylaxis

Patients with Fontan physiology are at heightened risk of thrombosis related to passive venous return leading to increased stasis, as well as acquired thrombophilia from congestive hepatopathy. Variability exists for post-Fontan thromboprophylaxis, with no consensus on best practices. Direct oral anticoagulants offer advantages over conventional anticoagulants including fewer drug-drug interactions, no dietary restrictions, and less frequent monitoring. Herein, we report our single center experience utilizing apixaban thromboprophylaxis in children post-Fontan procedure. Single center, retrospective, cohort study evaluating apixaban thromboprophylaxis dosing strategies, efficacy, and safety in children admitted post-Fontan procedure at Boston Children's Hospital. Between September 2019 and December 2023, 62 children, median age 3.2 years (2.1-10.5 years), weight 13.9 kg (9.5-56.3 kg) received apixaban at a median of 93 days post-Fontan (7-1421 days). Over a total of 93 days of apixaban exposure, there was 1 treatment-related thrombosis event (0.07 per 1000 person-days on apixaban) and 3 combined treatment-related clinically relevant non-major (CRNM) and major bleeding events (0.22 per 1000 person-days on apixaban). Apixaban for post-Fontan thromboprophylaxis was feasible with low rates of bleeding and thrombosis.

Direct oral anticoagulant use in hospitalized pediatric patients: Insights from nationwide data

BACKGROUND

Direct oral anticoagulants (DOACs) have had significant impact on the management of venous thromboembolism (VTE) in adults, but these agents were not approved for use in pediatric patients until 2021. Our objective was to analyze the characteristics of pediatric patients treated with DOACs prior to and following U.S. Food and Drug Administration (FDA) approval for children and evaluate their impact on hospital outcomes.

PROCEDURE

We utilized the Epic Cosmos dataset (Cosmos), a de-identified dataset of over 220 million patients, to identify patients aged 1-18 years admitted with a first-occurrence diagnosis of VTE between January 1, 2017 and June 30, 2023. Patients were grouped by anticoagulation received (unfractionated heparin, low molecular weight heparin, and/or DOACs).

RESULTS

Among 5138 eligible patients, 18.1% received DOACs as all or part of their anticoagulation treatment, while 81.9% received heparin therapies alone. Patients treated with DOACs were older than patients treated with heparin monotherapy at 17.4 and 13.0 years, respectively. Non-DOAC patients were more likely to have chronic conditions and were less likely to have pulmonary embolism. Patients treated with DOACs demonstrated shorter overall length of stay and duration of intensive care unit (ICU) admission.

CONCLUSIONS

DOACs remain infrequently utilized in pediatric patients, especially in those under 13 years old. Initiation on heparin therapy and transition to DOACs remains common, with 80.6% of DOAC patients receiving heparin during their hospitalization. While DOAC monotherapy is not currently endorsed as first-line therapy for DVT or PE in children, it is being used clinically. Further research is needed to clarify the impact of DOAC use on patient adherence, VTE recurrence, and healthcare cost.

Anticoagulation in Pediatric Patients

The use of antithrombotic agents is increasing in infants, children and adolescents. The more recent routine inclusion of children in FDA-monitored clinical trials has propelled the rapid accumulation of safety and efficacy data on these agents in pediatric patients. Antithrombotic agents in current use include indirect or antithrombin-dependent anticoagulants, intravenous direct thrombin inhibitors, direct oral anticoagulants (DOACs) targeting thrombin or factor Xa, antiplatelet agents and thrombolytic therapies. Each class of antithrombotic agent has distinct mechanisms of action, clearance routes, half-lives, safety and dosing. Anticoagulant efficacy is dependent upon the specific clinical indication and stability of the pediatric patient. Duration of anticoagulant course is also dependent upon the clinical indication as well as rate of thrombus resolution. This manuscript reviews the mechanism of action, route of administration, route of clearance and plasma half-life for the antithrombotic agents in current use in children. Use of anticoagulation in the context of thrombolytic therapy is discussed.

Real-world experience of direct oral anticoagulant use in a single pediatric center

BACKGROUND

Pediatric venous thromboembolism has increased by 130%-200%, specifically in hospitalized children, and direct oral anticoagulants (DOACs) offer several therapeutic advantages.

METHODS

This study aims to evaluate the real-world epidemiological and outcome data from a retrospective review of pediatric patients treated with DOACs from January 1, 2013 to December 31, 2022. In this single-center, IRB-approved study, 65 patients were identified and analyzed using SPSS statistical software, and a descriptive statistical analysis was conducted.

RESULTS

Of the 65 patients, 37% were on apixaban, 61.5% were on rivaroxaban, and 1.5% were on dabigatran. Per the 2023 ISTH outcome definitions, one (2%) patient had a major bleeding episode, six (9%) had clinically relevant non-major bleeding, three (5%) patients had patient-important heavy menstrual bleeding (HMB), and one (1.5%) patient had minor bleeding. Seven (19%) of 37 postmenarchal patients had evidence of HMB. Six (9.2%) patients had recurrent venous thromboembolism while on a DOAC (one was on apixaban, and five were on rivaroxaban) and were transitioned to other forms of anticoagulation.

CONCLUSION

Thus, bleeding rates after DOAC therapy are comparable to previous DOAC trials, as well as other anticoagulants in pediatrics. HMB is an important outcome measure and should continue to be investigated. This study reports a higher rate of recurrent thrombosis (9.2%) compared to other trials. However, this observation may be attributed to patients who had ongoing risk factors, as well as a longer duration of study follow-up. Additional multicentered outcome studies evaluating DOAC use in children are needed to determine long-term recurrence and HMB risks.

Real-world experience with edoxaban for anticoagulation in children at risk for coronary artery thrombosis

BACKGROUND

Direct oral anticoagulants have the potential to improve care in children requiring chronic anticoagulation. Edoxaban has favourable pharmacokinetics that could benefit younger patients but data on long-term safety and efficacy for specific paediatric indications are lacking.

STUDY AIMS

We present a single-centre experience using edoxaban in children who require chronic anticoagulation for large coronary artery aneurysms secondary to Kawasaki disease.

METHODS

Weight-based dosing of once-daily oral edoxaban was offered as alternative to standard anticoagulation for patients aged 1-18 years. Chart review was performed for a median follow-up period of 49 months on edoxaban. Steady-state pharmacokinetics and pharmacodynamics of edoxaban were also explored.

RESULTS

Sixteen patients on chronic therapy with edoxaban were included. No major bleeding events were reported. Two patients experienced coronary artery thrombosis after 23 and 38 months on edoxaban, 7 and 11 years after diagnosed with Kawasaki disease, respectively. This predicts 70% event-free rate at 12 years from diagnosis. Area under the curve estimates over the dosing interval of 24 hours were similar to those reported in adults.

CONCLUSIONS

Edoxaban use is feasible and well-tolerated for long-term use in paediatric population. We suggest appropriate exposure using weight-based once-daily dosing strategy that may be comparable to standard-of-care anticoagulation in prevention of coronary artery thrombosis. Larger studies are needed to evaluate long-term safety and efficacy of edoxaban in this population.

Use of apixaban in children awaiting heart transplantation

BACKGROUND

The use of apixaban in the pediatric cardiac population is expanding. We describe our apixaban dosing and monitoring strategy in children and young adults awaiting heart transplantation, along with outcomes related to bleeding and thrombosis during wait-list and early post-transplant periods.

METHODS

This study is a retrospective, single-center analysis of all patients receiving apixaban while awaiting cardiac transplantation. Weight-based dosing was monitored with peak drug-specific anti-Xa chromogenic analysis. Significant post-operative bleeding defined by chest tube output or need for surgical intervention.

RESULTS

From September 2020 to December 2022, 19 patients, median age 13.5 years (6.1, 15.8 years), weighing 48.9 kg (15.4, 67.6) received apixaban while awaiting transplant. Indication for apixaban was prophylaxis (n = 18, 3 with ventricular assist devices) and treatment of thrombus (n = 1). There were no clinically relevant non-major or major bleeding, nor thrombotic events while awaiting transplant. The median time from last apixaban dose to arrival in the operating room was 23.2 h (15.6-33.8), with median random apixaban level of 37 ng/mL (28.3, 59), 6.3 h (4.8, 8.4) prior to arrival in the operating room. In this study, 32% of patients had significant post-operative bleeding based on chest tube output post-transplant or need for intervention. No patients meeting criteria for significant post-operative bleeding were thought to be attributable to apixaban.

CONCLUSIONS

Careful use of apixaban can be safe and effective while awaiting heart transplant. There was no appreciable increase in peri-operative bleeding. The use of apixaban is promising in providing safe, predictable and efficacious anticoagulation while avoiding additional patient stressors.

Systematic Review of Randomized Clinical Trials on Direct Oral Anticoagulants in Pediatric Heart Diseases

BACKGROUND

Direct oral anticoagulants (DOACs) have been widely applied in adults for thrombosis prophylaxis. However, the effect of DOACs in pediatric patients with congenital or acquired heart diseases who need anticoagulation therapy remains unclear.

METHODS

We systematically searched the databases of PubMed, Embase, and the Cochrane Library, as well as the ClinicalTrials.gov registry and the World Health Organization's International Clinical Trials Registry Platform until June 2024 to identify relevant randomized clinical trials (RCTs). If the number of included studies was less than 5, we performed a narrative review to assess the effect of DOACs in pediatric patients.

RESULTS

Four studies were included. In the UNIVERSE study, thrombotic events occurred in 2% of the rivaroxaban group and 9% of the aspirin group, with bleeding events in 36% and 41%, respectively. The ENNOBLE-ATE study showed no thromboembolic events in the edoxaban group and 1.7% in the SOC group (rate difference: -0.07%, 95% CI: -0.22 to 0.07%). Major bleeding rates were similar (rate difference: -0.03%, 95% CI: -0.18 to 0.12%). The SAXOPHONE trial showed no thromboembolic events in either group and similar major bleeding rates (-0.8%, 95% CI: -8.1 to 3.3%). In the DIVERSITY trial, 81% of dabigatran patients achieved the primary outcome versus 59.3% in the SOC group (Odds ratio: 0.342, 95% CI: 0.081-1.229). No major bleeding occurred in either group.

CONCLUSION

Existing studies suggest that the use of DOACs hold promise as an effective and safe alternative for preventing and treating thromboembolism in pediatric patients with heart conditions.

Therapeutic Drug Monitoring of Direct Oral Anticoagulants in Patients with Extremely Low and High Body Weight-Pilot Study

Phase III clinical trials for individual direct oral anticoagulants (DOACs) contained a limited representation of subjects with abnormal body weight, which were mostly limited to a BMI > 40 kg/m2, or body weight > 120 kg for obese subjects, and <50 kg for underweight subjects. Although low or high body weight is not a contraindication to DOACs therapy, it can significantly affect the safety and effectiveness of treatment. Due to the limited amount of clinical data on the use of DOACs in extremely abnormal weight ranges, optimal pharmacotherapy in this group of patients is a matter of controversy. The objective of this study was to evaluate the pharmacokinetics of DOAC properties in patients with abnormal body weight beyond the established cut-off points in the phase III studies for rivaroxaban, apixaban, and dabigatran. In total, 38 patients took DOACs for at least 12 months for non-valvular atrial fibrillation in 2019-2021. Blood samples were collected before the planned intake of the drug and 4 h after its administration. The determined concentrations of DOACs were statistically analyzed in relation to body weight, age, and eGFR (estimated Glomerular Filtration Rate). Among subjects taking apixaban, rivaroxaban, and dabigatran, the smallest representation of patients who achieved therapeutic concentrations were those treated with dabigatran. The population of people with abnormal body weight is a potential risk group of patients, in which some of them do not reach the therapeutic range of DOACs.