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

BACKGROUND: Direct oral anticoagulants use in pediatric cardiology is poorly defined. OBJECTIVE: We present the largest experience of apixaban use in children with heart disease, using weight- and level-based dosing. METHODS: Retrospective single-center analysis of cardiac patients ≤19 years treated with apixaban. Patients were evaluated for safety (clinically relevant non-major [CRNM] or major bleeding; thrombotic events) and effectiveness (thrombus improvement by imaging). Peak drug-specific anti-Xa chromogenic assay results ("apixaban levels") were analyzed. RESULTS: Over 3 years (5/2018-9/2021), 219 children, median age 6.8 years (0.3-19), median weight 20.8 kg (4.8-160) received apixaban, totaling 50,916 patient days. Of them, 172 (79%) warranted thromboprophylaxis and 47 (21%) thrombosis treatment (with 10 arterial, 19 venous, 15 intracardiac, and 3 pulmonary). The median initial peak apixaban level was 165 ng/mL (23-474; n = 125) in the prophylaxis subgroup and 153 ng/mL (30-450; n = 33) in the treatment subgroup; dosage was adjusted in response to levels in 25% of the patients. There were 4 bleeding safety events (3 CRNM; 1 major, hemoptysis complicating empyema); the serious bleeding event rate was 2.9 per 100 patient-years of apixaban. Minor bleeding events (42) were noted in 18 patients, with an additional 2 having leukopenia, 1 transaminitis, and 3 rashes. An improvement in thrombosis was seen in 95% of the treated patients with available follow-up imaging (37/39 patients). CONCLUSION: Apixaban use was feasible with a low rate of adverse events across a diverse pediatric cardiac population using commercially available tablets dosed to weight and adjusted based on peak apixaban levels.

Apixaban Anticoagulation in Children and Young Adults Supported With the HeartMate 3 Ventricular Assist Device.

There is a growing population of pediatric and adult patients supported with the HeartMate 3 ventricular assist device (HM3 VAD) all of whom require anticoagulation. Apixaban is an anticoagulant requiring less testing than warfarin which has been shown to be effective in other indications. We report five pediatric and young adult patients managed on HM3 VAD with apixaban anticoagulation for 1589 days of VAD support between January 6, 2019 and January 7, 2022. The median age was 17 years and the weight was 69 kg. Four patients had congenital heart disease (2 single-ventricle Fontan circulation, and 2 biventricular circulations) and one had dilated cardiomyopathy. Apixaban was initiated at a median of 7 days postoperatively and doses were titrated based on peak apixaban-specific anti-Xa chromogenic analysis levels (goal 150-250 ng/ml). All patients received aspirin 81 mg daily. There was one major hemocompatibility-related event observed (outflow graft thrombus in the setting of medication nonadherence and chronic VAD infection); there was no major bleeding, death, or stroke. Three patients underwent heart transplantation and two remain on VAD support. In this limited series, apixaban paired with a level-based dosing regimen and low-dose aspirin provided safe and effective antithrombosis with only one hemocompatibility-related event related to medication non-adherence.

Decreased Risk of Strokes in Children with Ventricular Assist Devices Within ACTION.

We sought to characterize strokes in children with ventricular assist devices. Of 407 patients in the ACTION registry (4/1/18-5/3/2021), 45 (11%) experienced 52 strokes (45 ischemic and 7 hemorrhagic). Median time to stroke was 23.5 days and 19/52 (37%) occurred ≤ 10 days. Stroke rate was 0.09 and 0.63 strokes per patient-year for implantable continuous and paracorporeal devices, respectively. Patients with stroke were younger, more likely to have congenital heart disease and have been on extracorporeal membrane oxygenation at time of VAD. Based on these data, ACTION is now focused on decreasing strokes in these higher-risk patients with particular attention to the peri-implant period.

Design and pilot testing of therapeutic clothing for hospitalized children.

PURPOSE: The purpose of this paper is to describe the design and pilot program of a parent designed clothing option for hospitalized infants and children and to better understand the importance and effects of hospital clothing on families. Little research has been done on how clothing a hospitalized child impacts the child's quality of life and their parent's perception of care. Research has been limited to clothing in adults and its relation to infection. DESIGN AND METHODS: A pediatric outfit (the Georgie) for hospitalized infants and children was designed based on insight from bedside nursing, physicians, parents, and supply chain personnel. The garment was pilot tested on select patients from intensive care units of a large children's hospital. A pre- and post-use questionnaire was disseminated with questions focused on aspects of the child's care, comfort in changing child's clothes/diapers, number of times the Georgie was used and comfort level of using the Georgie. Survey responses were summarized using descriptive statistics. RESULTS: Parents overall response to the Georgie was positive with great value placed on having their child dressed. All parents (n = 5) responded that too many lines were an obstacle to having their child dressed. Compared to the hospital Johnny, the Georgie (80%, n = 4) was the most preferred when placement and securement of monitoring lines was taken into consideration with one parent preferring a blanket and diaper only. Nurses felt the benefit outweighed the added effort in dressing the patient. The majority of the nurses had a positive initial reaction to the Georgie (80%, n = 4) and felt the lines or external devices were "very secure/secure" (80%, n = 4) when the patient was wearing the Georgie. PRACTICE IMPLICATIONS: Implementing a new family centered care initiative of dressing critically ill patients in the Georgie may improve patient and family's quality of life while hospitalized. A larger scale study is indicated to assess the importance of dressing hospitalized pediatric patients for their families, to clarify the effect on nursing care, to optimize ability to stabilize lines, and to understand logistical issues.

Coagulation profiles and viscoelastic testing in multisystem inflammatory syndrome in children.

OBJECTIVE: To characterize viscoelastic testing profiles of children with multisystem inflammatory syndrome in children (MIS-C). METHODS: This single-center retrospective review included 30 patients diagnosed with MIS-C from March 1 to September 1, 2020. Thromboelastography (TEG) with platelet mapping was performed in 19 (63%) patients and compared to age- and sex-matched controls prior to cardiac surgery. Relationships between TEG parameters and inflammatory markers were assessed using correlation. RESULTS: Patients with MIS-C had abnormal TEG results compared to controls, including decreased kinetic (K) time (1.1 vs. 1.7 minutes, p < .01), increased alpha angle (75.0° vs. 65.7°, p < .01), increased maximum amplitude (70.8 vs. 58.3 mm, p < .01), and decreased lysis in 30 minutes (Ly30) (1.1% vs. 3.7%, p = .03); consistent with increased clot formation rate and strength, and reduced fibrinolysis. TEG maximum amplitude was moderately correlated with erythrocyte sedimentation rate (ESR) (r = 0.60, p = .02), initial platelet count (r = 0.67, p < .01), and peak platelet count (r = 0.51, p = .03). TEG alpha angle was moderately correlated with peak platelet count (r = 0.54, p = .02). Seventeen (57%) patients received aspirin (ASA) and anticoagulation, five (17%) received only ASA, and three (10%) received only anticoagulation. No patients had a symptomatic thrombotic event. Six (20%) patients had a bleeding event, none of which was major. CONCLUSIONS: Patients with MIS-C had evidence of hypercoagulability on TEG. Increased ESR and platelets were associated with higher clot strength. Patients were prophylactically treated with ASA or anticoagulation with no symptomatic thrombosis or major bleeding. Further multicenter study is required to characterize the rate of thrombosis and optimal thromboprophylaxis algorithm in this patient population.

Berlin Heart EXCOR and ACTION post-approval surveillance study report.

BACKGROUND: The Berlin Heart EXCOR Pediatric (EXCOR) ventricular assist device (VAD) was introduced in North America nearly 2 decades ago. The EXCOR was approved under Humanitarian Device Exemption status in 2011 and received post-market approval (PMA) in 2017 from Food and Drug Administration. Since the initial approval, the field of pediatric mechanical circulatory support has changed, specifically with regard to available devices, anticoagulation strategies, and the types of patients supported. This report summarizes the outcomes of patients supported with EXCOR from the Advanced Cardiac Therapies Improving Outcomes Network (ACTION) registry. These data were part of the PMA surveillance study (PSS) required by the Food and Drug Administration. METHODS: ACTION is a learning collaborative of over 40 pediatric heart failure programs worldwide, which collects data for all VAD implantations as one of its initiatives. All patients in North America with EXCOR implants reported to ACTION from 2018 to 2020 (n = 72) who had met an outcome were included in the EXCOR PSS group. This was compared with a historical, previously reported Berlin Heart EXCOR study group (Berlin Heart study [BHS] group, n = 320, 2007‒2014). RESULTS: Patients in the PSS group were younger, were smaller in weight/body surface area, were more likely to have congenital heart disease, and were less likely to receive a bi-VAD than those in the BHS group. Patients in the PSS group were less likely to be in Interagency Registry for Mechanically Assisted Circulatory Support Profile 1 and were supported for a longer duration. The primary anticoagulation therapy for 92% of patients in the PSS group was bivalirudin. Success, defined as being transplanted, being weaned for recovery, or being alive on a device at 180 days after implantation, was 86% in the PSS group compared with 76% in the BHS group. Incidence of stroke was reduced by 44% and the frequency of pump exchange by 40% in the PSS group compared with those in the BHS group. Similarly, all other adverse events, including major bleeding, were reduced in the PSS group. CONCLUSIONS: The PSS data, collected through ACTION, highlight the improvement in outcomes for patients supported with EXCOR compared with the outcomes in a historical cohort. These findings may be the result of changes in patient care practices over time and collaborative learning.

Utilization and Outcomes of Children Treated with Direct Thrombin Inhibitors on Paracorporeal Ventricular Assist Device Support.

Thrombotic and bleeding complications have historically been major causes of morbidity and mortality in pediatric ventricular assist device (VAD) support. Standard anticoagulation with unfractionated heparin is fraught with problems related to its heterogeneous biochemical composition and unpredictable pharmacokinetics. We sought to describe the utilization and outcomes in children with paracorporeal VAD support who are treated with direct thrombin inhibitors (DTIs) antithrombosis therapy. Retrospective multicenter review of all pediatric patients (aged <19 years) treated with a DTI (bivalirudin or argatroban) on paracorporeal VAD support, examining bleeding and thrombotic adverse events. From May 2012 to 2018, 43 children (21 females) at 10 centers in North America, median age 9.5 months (0.1-215 months) weighing 8.6 kg (2.8-150 kg), were implanted with paracorporeal VADs and treated with a DTI. Diagnoses included cardiomyopathy 40% (n = 17), congenital heart disease 37% (n = 16; single ventricle n = 5), graft vasculopathy 9% (n = 4), and other 14% (n = 6). First device implanted included Berlin Heart EXCOR 49% (n = 21), paracorporeal continuous flow device 44% (n = 19), and combination of devices in 7% (n = 3). Adverse events on DTI therapy included; major bleeding in 16% (n = 7) (2.6 events per 1,000 patient days of support on DTI), and stroke 12% (n = 5) (1.7 events per 1,000 patient days of support on DTI). Overall survival to transplantation (n = 30) or explantation (n = 8) was 88%. This is the largest multicenter experience of DTI use for anticoagulation therapy in pediatric VAD support. Outcomes are encouraging with lower major bleeding and stroke event rate than that reported in literature using other anticoagulation agents in pediatric VAD support.

Outcomes of children supported with an intracorporeal continuous-flow left ventricular assist system.

BACKGROUND: Since 2012, there has been growing use of the HeartWare (Medtronic, Mounds View, MN) intracorporeal continuous flow (CF) ventricular assist device (VAD) in children, despite it not being labeled for use in pediatric patients. We sought to describe the use and outcomes of children with HeartWare VADs. METHODS: We identified all patients aged < 19 years and young adults aged 19 to 30 years supported with HeartWare who were entered into the pediatric portion (Pedimacs) of the Interagency Registry for Mechanically Assisted Circulatory Support (Intermacs) and the Intermacs registries, respectively, between September 2012 and June 2017. Adverse events and outcomes were analyzed and compared. RESULTS: We identified 192 children and 247 young adult HeartWare patients. Baseline characteristics of children differed from young adults, with lower median weight of 51.5 kg (range, 13.1-162) vs 75.8 kg (range, 29.8-191; p ≤ 0.0001) and body surface area of 1.5 m2 (range, 0.6-2.9 m2) vs 1.9 m2 (range, 1.1-3.2 m2; p ≤ 0.0001) . At the time of implant, 12 children weighed < 20 kg, and 58.3% of these children had congenital heart disease compared with 11.7% in children who weighed ≥ 20 kg and 6.1% in young adults (p ≤ 0.0001). Median duration of support was 2.8 months (IQR, 1.3-6.0 months) in children and 9.7 months (IQR 4.0-19.2 months) in young adults (p ≤ 0.0001). Serious adverse events in children and young adults included infection in 27% and 44% of patients, respectively (p=0.0002), major bleeding in 23% and 23%, respectively (p = 0.9), device malfunction/pump thrombosis in 11% and 19.0%, respectively (p = 0.04), and stroke in 10% and 12%, respectively (p = 0.5). Of the children who weighed < 20 kg at time of implant, 0% had major bleeding, 16.7% had infections, and 8.3% had stroke. Overall survival was not statistically different between children and young adults, and there was no increased mortality in children who weighed < 20 kg. Rate of discharge on HeartWare was 80% in young adults vs 48% in children who weighed ≥ 20 kg and only 33% in children who weighed < 20 kg. CONCLUSIONS: Survival in children supported with HeartWare is encouraging and comparable to young adults; however, adverse events are not uncommon in children. Ongoing evaluation of the HeartWare use in children is necessary to further decrease the rate of adverse events and understand obstacles to discharge.

The Evolution of a Pediatric Ventricular Assist Device Program: The Boston Children's Hospital Experience.

Mechanical circulatory support in the form of ventricular assist devices (VADs) in children has undergone rapid growth in the last decade. With expansion of device options available for larger children and adolescents, the field of outpatient VAD support has flourished, with many programs unprepared for the clinical, programmatic, and administrative responsibilities. From preimplantation VAD evaluation and patient education to postimplant VAD management, the VAD program, staffed with an interdisciplinary team, is essential to providing safe, effective, and sustainable care for a new technology in an exceedingly complex patient population. Herein, this paper describes the Boston Children's Hospital VAD experience over a decade and important lessons learned from developing a pediatric program focusing on a high-risk but low-volume population. We highlight the paramount role of the VAD coordinator, clinical infrastructure requirements, as well as innovation in care spanning inpatient and outpatient VAD supports at Boston Children's Hospital.