Apixaban for Prevention of Thromboembolism in Pediatric Heart Disease

BACKGROUND

Children with heart disease frequently require anticoagulation for thromboprophylaxis. Current standard of care (SOC), vitamin K antagonists or low-molecular-weight heparin, has significant disadvantages.

OBJECTIVES

The authors sought to describe safety, pharmacokinetics (PK), pharmacodynamics, and efficacy of apixaban, an oral, direct factor Xa inhibitor, for prevention of thromboembolism in children with congenital or acquired heart disease.

METHODS

Phase 2, open-label trial in children (ages, 28 days to <18 years) with heart disease requiring thromboprophylaxis. Randomization 2:1 apixaban or SOC for 1 year with intention-to-treat analysis.

PRIMARY ENDPOINT

a composite of adjudicated major or clinically relevant nonmajor bleeding. Secondary endpoints: PK, pharmacodynamics, quality of life, and exploration of efficacy.

RESULTS

From 2017 to 2021, 192 participants were randomized, 129 apixaban and 63 SOC. Diagnoses included single ventricle (74%), Kawasaki disease (14%), and other heart disease (12%). One apixaban participant (0.8%) and 3 with SOC (4.8%) had major or clinically relevant nonmajor bleeding (% difference -4.0 [95% CI: -12.8 to 0.8]). Apixaban incidence rate for all bleeding events was nearly twice the rate of SOC (100.0 vs 58.2 per 100 person-years), driven by 12 participants with ≥4 minor bleeding events. No thromboembolic events or deaths occurred in either arm. Apixaban pediatric PK steady-state exposures were consistent with adult levels.

CONCLUSIONS

In this pediatric multinational, randomized trial, bleeding and thromboembolism were infrequent on apixaban and SOC. Apixaban PK data correlated well with adult trials that demonstrated efficacy. These results support the use of apixaban as an alternative to SOC for thromboprophylaxis in pediatric heart disease. (A Study of the Safety and Pharmacokinetics of Apixaban Versus Vitamin K Antagonist [VKA] or Low Molecular Weight Heparin [LMWH] in Pediatric Subjects With Congenital or Acquired Heart Disease Requiring Anticoagulation; NCT02981472).

The Fontan Udenafil Exercise Longitudinal Trial: Subgroup Analysis

The Pediatric Heart Network's Fontan Udenafil Exercise Longitudinal (FUEL) Trial (Mezzion Pharma Co. Ltd., NCT02741115) demonstrated improvements in some measures of exercise capacity and in the myocardial performance index following 6 months of treatment with udenafil (87.5 mg twice daily). In this post hoc analysis, we evaluate whether subgroups within the population experienced a differential effect on exercise performance in response to treatment. The effect of udenafil on exercise was evaluated within subgroups defined by baseline characteristics, including peak oxygen consumption (VO2), serum brain-type natriuretic peptide level, weight, race, gender, and ventricular morphology. Differences among subgroups were evaluated using ANCOVA modeling with fixed factors for treatment arm and subgroup and the interaction between treatment arm and subgroup. Within-subgroup analyses demonstrated trends toward quantitative improvements in peak VO2, work rate at the ventilatory anaerobic threshold (VAT), VO2 at VAT, and ventilatory efficiency (VE/VCO2) for those randomized to udenafil compared to placebo in nearly all subgroups. There was no identified differential response to udenafil based on baseline peak VO2, baseline BNP level, weight, race and ethnicity, gender, or ventricular morphology, although participants in the lowest tertile of baseline peak VO2 trended toward larger improvements. The absence of a differential response across subgroups in response to treatment with udenafil suggests that the treatment benefit may not be restricted to specific sub-populations. Further work is warranted to confirm the potential benefit of udenafil and to evaluate the long-term tolerability and safety of treatment and to determine the impact of udenafil on the development of other morbidities related to the Fontan circulation.Trial Registration NCT0274115.

Examination of Adverse Reactions After COVID-19 Vaccination Among Patients With a History of Multisystem Inflammatory Syndrome in Children

Importance

Data are limited regarding adverse reactions after COVID-19 vaccination in patients with a history of multisystem inflammatory syndrome in children (MIS-C). The lack of vaccine safety data in this unique population may cause hesitancy and concern for many families and health care professionals.

Objective

To describe adverse reactions following COVID-19 vaccination in patients with a history of MIS-C.

Design, Setting, and Participants

In this multicenter cross-sectional study including 22 North American centers participating in a National Heart, Lung, and Blood Institute, National Institutes of Health-sponsored study, Long-Term Outcomes After the Multisystem Inflammatory Syndrome in Children (MUSIC), patients with a prior diagnosis of MIS-C who were eligible for COVID-19 vaccination (age ≥5 years; ≥90 days after MIS-C diagnosis) were surveyed between December 13, 2021, and February 18, 2022, regarding COVID-19 vaccination status and adverse reactions.

Exposures

COVID-19 vaccination after MIS-C diagnosis.

Main Outcomes and Measures

The main outcome was adverse reactions following COVID-19 vaccination. Comparisons were made using the Wilcoxon rank sum test for continuous variables and the χ2 or Fisher exact test for categorical variables.

Results

Of 385 vaccine-eligible patients who were surveyed, 185 (48.1%) received at least 1 vaccine dose; 136 of the vaccinated patients (73.5%) were male, and the median age was 12.2 years (IQR, 9.5-14.7 years). Among vaccinated patients, 1 (0.5%) identified as American Indian/Alaska Native, non-Hispanic; 9 (4.9%) as Asian, non-Hispanic; 45 (24.3%) as Black, non-Hispanic; 59 (31.9%) as Hispanic or Latino; 53 (28.6%) as White, non-Hispanic; 2 (1.1%) as multiracial, non-Hispanic; and 2 (1.1%) as other, non-Hispanic; 14 (7.6%) had unknown or undeclared race and ethnicity. The median time from MIS-C diagnosis to first vaccine dose was 9.0 months (IQR, 5.1-11.9 months); 31 patients (16.8%) received 1 dose, 142 (76.8%) received 2 doses, and 12 (6.5%) received 3 doses. Almost all patients received the BNT162b2 vaccine (347 of 351 vaccine doses [98.9%]). Minor adverse reactions were observed in 90 patients (48.6%) and were most often arm soreness (62 patients [33.5%]) and/or fatigue (32 [17.3%]). In 32 patients (17.3%), adverse reactions were treated with medications, most commonly acetaminophen (21 patients [11.4%]) or ibuprofen (11 [5.9%]). Four patients (2.2%) sought medical evaluation, but none required testing or hospitalization. There were no patients with any serious adverse events, including myocarditis or recurrence of MIS-C.

Conclusions and Relevance

In this cross-sectional study of patients with a history of MIS-C, no serious adverse events were reported after COVID-19 vaccination. These findings suggest that the safety profile of COVID-19 vaccination administered at least 90 days following MIS-C diagnosis appears to be similar to that in the general population.

Diastolic Dysfunction With Preserved Ejection Fraction After the Fontan Procedure

Background Heart failure phenotyping in single-ventricle Fontan patients is challenging, particularly in patients with normal ejection fraction (EF). The objective of this study was to identify Fontan patients with abnormal diastolic function, who are high risk for heart failure with preserved ejection fraction (HFpEF), and characterize their cardiac mechanics, exercise function, and functional health status. Methods and Results Data were obtained from the Pediatric Heart Network Fontan Cross-sectional Study database. EF was considered abnormal if <50%. Diastolic function was defined as abnormal if the diastolic pressure:volume quotient (lateral E:e'/end-diastolic volume) was >90th percentile (≥0.26 mL-1). Patients were divided into: controls=normal EF and diastolic function; systolic dysfunction (SD) = abnormal EF with normal diastolic function; diastolic dysfunction (DD) = normal EF with abnormal diastolic pressure:volume quotient. Exercise function was quantified as percent predicted peak VO2. Physical Functioning Summary Score (FSS) was reported from the Child Health Questionnaire. A total of 239 patients were included, 177 (74%) control, 36 (15%) SD, and 26 (11%) DD. Median age was 12.2 (5.4) years. Arterial elastance, a measure of arterial stiffness, was higher in DD (3.6±1.1 mm Hg/mL) compared with controls (2.5±0.8 mm Hg/mL), P<0.01. DD patients had lower predicted peak VO2 compared with controls (52% [20] versus 67% [23], P<0.01). Physical FSS was lower in DD (45±13) and SD (44±13) compared with controls (50±7), P<0.01. Conclusions Fontan patients with abnormal diastolic function and normal EF have decreased exercise tolerance, decreased functional health status, and elevated arterial stiffness. Identification of patients at high risk for HFpEF is feasible and should be considered when evaluating Fontan patients.

Clinically Suspected Myocarditis Temporally Related to COVID-19 Vaccination in Adolescents and Young Adults

BACKGROUND

Understanding the clinical course and short-term outcomes of suspected myocarditis following COVID-19 vaccination has important public health implications in the decision to vaccinate youth.

METHODS

We retrospectively collected data on patients <21 years-old presenting before 7/4/2021 with suspected myocarditis within 30 days of COVID-19 vaccination. Lake Louise criteria were used for cardiac magnetic resonance imaging (cMRI) findings. Myocarditis cases were classified as confirmed or probable based on the Centers for Disease Control and Prevention definitions.

RESULTS

We report on 139 adolescents and young adults with 140 episodes of suspected myocarditis (49 confirmed, 91 probable) at 26 centers. Most patients were male (N=126, 90.6%) and White (N=92, 66.2%); 29 (20.9%) were Hispanic; and median age was 15.8 years (range 12.1-20.3, IQR 14.5-17.0). Suspected myocarditis occurred in 136 patients (97.8%) following mRNA vaccine, with 131 (94.2%) following the Pfizer-BioNTech vaccine; 128 (91.4%) occurred after the 2nd dose. Symptoms started a median of 2 days (range 0-22, IQR 1-3) after vaccination. The most common symptom was chest pain (99.3%). Patients were treated with nonsteroidal anti-inflammatory drugs (81.3%), intravenous immunoglobulin (21.6%), glucocorticoids (21.6%), colchicine (7.9%) or no anti-inflammatory therapies (8.6%). Twenty-six patients (18.7%) were in the ICU, two were treated with inotropic/vasoactive support, and none required ECMO or died. Median hospital stay was 2 days (range 0-10, IQR 2-3). All patients had elevated troponin I (N=111, 8.12 ng/mL, IQR 3.50-15.90) or T (N=28, 0.61 ng/mL, IQR 0.25-1.30); 69.8% had abnormal electrocardiograms and/or arrythmias (7 with non-sustained ventricular tachycardia); and 18.7% had left ventricular ejection fraction (LVEF) <55% on echocardiogram. Of 97 patients who underwent cMRI at median 5 days (range 0-88, IQR 3-17) from symptom onset, 75 (77.3%) had abnormal findings: 74 (76.3%) had late gadolinium enhancement, 54 (55.7%) had myocardial edema, and 49 (50.5%) met Lake Louise criteria. Among 26 patients with LVEF <55% on echocardiogram, all with follow-up had normalized function (N=25).

CONCLUSIONS

Most cases of suspected COVID-19 vaccine myocarditis occurring in persons <21 years have a mild clinical course with rapid resolution of symptoms. Abnormal findings on cMRI were frequent. Future studies should evaluate risk factors, mechanisms, and long-term outcomes.

Medium-Term Complications Associated With Coronary Artery Aneurysms After Kawasaki Disease: A Study From the International Kawasaki Disease Registry

Background

Coronary artery aneurysms (CAAs) may occur after Kawasaki disease (KD) and lead to important morbidity and mortality. As CAA in patients with KD are rare and heterogeneous lesions, prognostication and risk stratification are difficult. We sought to derive the cumulative risk and associated factors for cardiovascular complications in patients with CAAs after KD.

Methods and Results

A 34‐institution international registry of 1651 patients with KD who had CAAs (maximum CAA Z score ≥2.5) was used. Time‐to‐event analyses were performed using the Kaplan–Meier method and Cox proportional hazard models for risk factor analysis. In patients with CAA Z scores ≥10, the cumulative incidence of luminal narrowing (>50% of lumen diameter), coronary artery thrombosis, and composite major adverse cardiovascular complications at 10 years was 20±3%, 18±2%, and 14±2%, respectively. No complications were observed in patients with a CAA Z score <10. Higher CAA Z score and a greater number of coronary artery branches affected were associated with increased risk of all types of complications. At 10 years, normalization of luminal diameter was noted in 99±4% of patients with small (2.5≤Z<5.0), 92±1% with medium (5.0≤Z<10), and 57±3% with large CAAs (Z≥10). CAAs in the left anterior descending and circumflex coronary artery branches were more likely to normalize. Risk factor analysis of coronary artery branch level outcomes was performed with a total of 893 affected branches with Z score ≥10 in 440 patients. In multivariable regression models, hazards of luminal narrowing and thrombosis were higher for patients with CAAs of the right coronary artery and left anterior descending branches, those with CAAs that had complex architecture (other than isolated aneurysms), and those with CAAs with Z scores ≥20.

Conclusions

For patients with CAA after KD, medium‐term risk of complications is confined to those with maximum CAA Z scores ≥10. Further risk stratification and close follow‐up, including advanced imaging, in patients with large CAAs is warranted.

Results of the FUEL Trial

BACKGROUND

The Fontan operation creates a total cavopulmonary connection, a circulation in which the importance of pulmonary vascular resistance is magnified. Over time, this circulation leads to deterioration of cardiovascular efficiency associated with a decline in exercise performance. Rigorous clinical trials aimed at improving physiology and guiding pharmacotherapy are lacking.

METHODS

The FUEL trial (Fontan Udenafil Exercise Longitudinal) was a phase III clinical trial conducted at 30 centers. Participants were randomly assigned udenafil, 87.5 mg twice daily, or placebo in a 1:1 ratio. The primary outcome was the between-group difference in change in oxygen consumption at peak exercise. Secondary outcomes included between-group differences in changes in submaximal exercise at the ventilatory anaerobic threshold, the myocardial performance index, the natural log of the reactive hyperemia index, and serum brain-type natriuretic peptide.

RESULTS

Between 2017 and 2019, 30 clinical sites in North America and the Republic of Korea randomly assigned 400 participants with Fontan physiology. The mean age at randomization was 15.5±2 years; 60% of participants were male, and 81% were white. All 400 participants were included in the primary analysis with imputation of the 26-week end point for 21 participants with missing data (11 randomly assigned to udenafil and 10 to placebo). Among randomly assigned participants, peak oxygen consumption increased by 44±245 mL/min (2.8%) in the udenafil group and declined by 3.7±228 mL/min (-0.2%) in the placebo group (P=0.071). Analysis at ventilatory anaerobic threshold demonstrated improvements in the udenafil group versus the placebo group in oxygen consumption (+33±185 [3.2%] versus -9±193 [-0.9%] mL/min, P=0.012), ventilatory equivalents of carbon dioxide (-0.8 versus -0.06, P=0.014), and work rate (+3.8 versus +0.34 W, P=0.021). There was no difference in change of myocardial performance index, the natural log of the reactive hyperemia index, or serum brain-type natriuretic peptide level.

CONCLUSIONS

In the FUEL trial, treatment with udenafil (87.5 mg twice daily) was not associated with an improvement in oxygen consumption at peak exercise but was associated with improvements in multiple measures of exercise performance at the ventilatory anaerobic threshold.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov. Unique identifier: NCT02741115.

Effects of race, ethnicity, and gender on surgical mortality in hypoplastic left heart syndrome

Information is limited regarding the effect of race, ethnicity, and gender on the outcomes of the three palliative procedures for hypoplastic left heart syndrome (HLHS). This study examined the effects of race, ethnicity, gender, type of admission, and surgical volume on in-hospital mortality associated with palliative procedures for HLHS between 1998 and 2007 using data from the University HealthSystem Consortium. According to the data, 1,949 patients underwent stage 1 palliation (S1P) with a mortality rate of 29 %, 1,279 patients underwent stage 2 palliations (S2P) with a mortality rate of 5.4 %, and 1,084 patients underwent stage 3 palliation (S3P) with a mortality rate of 4.1 %. The risk factors for increased mortality with S1P were black and "other" race, smaller surgical volume, and early surgical era. The only risk factors for increased mortality with S2P were black race (11 % mortality; odds ratio [OR], 3.19; 95 % confidence interval [CI] 1.69-6.02) and Hispanic ethnicity (11 % mortality; OR 3.30; 95 % CI 1.64-6.64). For S2P, no racial differences were seen in the top five surgical volume institutions, but racial differences were seen in the non-top-five surgical volume institutions. Mortality with S1P was significantly higher for patients discharged after birth (37 vs 24 %; p = 0.004), and blacks were more likely to be discharged after birth (12 vs 5 % for all other races; p < 0.001). No racial differences with S3P were observed. The risk factors for increased mortality at S1P were black and "other" race, smaller surgical volume, and early surgical era. The risk factors for increased in-hospital mortality with S2P were black race and Hispanic ethnicity.

Preoperative steroid treatment does not improve markers of inflammation after cardiac surgery in neonates: results from a randomized trial

OBJECTIVE

Neonatal cardiac surgery requiring cardiopulmonary bypass results in a heightened inflammatory response. Perioperative glucocorticoid administration is commonly used in an attempt to reduce the inflammatory cascade, although characterization of the cytokine response to steroids in neonatal cardiac surgery remains elusive because of highly variable approaches in administration. This randomized trial was designed to prospectively evaluate the effect of specific glucocorticoid dosing protocols on inflammatory markers in neonatal cardiac surgery requiring cardiopulmonary bypass.

METHODS

Neonates scheduled for cardiac surgery were randomly assigned to receive either 2-dose (8 hours preoperatively and operatively, n = 36) or single-dose (operatively, n = 32) methylprednisolone at 30 mg/kg per dose in a prospective double-blind trial. The primary outcome was the effect of these steroid regimens on markers of inflammation. Secondary analyses evaluated the association of specific cytokine profiles with postoperative clinical outcomes.

RESULTS

Patient demographics, perioperative variables, and preoperative indices of inflammation were similar between the single- and 2-dose groups. Preoperative cytokine response after the 2-dose methylprednisolone protocol was consistent with an anti-inflammatory effect, although this did not persist into the postoperative period. Premedication baseline levels of interleukin-6, interleukin-8, interleukin-10, and tumor necrosis factor α were predictive of postoperative intensive care unit and hospital length of stay. Only interleukin-8 demonstrated a postoperative response associated with duration of intensive care unit and hospital stay.

CONCLUSIONS

The addition of a preoperative dose of methylprednisolone to a standard intraoperative methylprednisolone dose does not improve markers of inflammation after neonatal cardiac surgery. The routine administration of preoperative glucocorticoids in neonatal cardiac surgery should be reconsidered.

Use of an administrative database to determine clinical management and outcomes in congenital heart disease

We review our 16-year experience using the large, multi-institutional database of the University HealthSystem Consortium to study management and outcomes in congenital heart surgery for hypoplastic left heart syndrome, transposition of the great arteries, and neonatal coarctation. The advantages, limitations, and use of administrative databases by others to study congenital heart surgery are reviewed.

Inpatient costs and charges for surgical treatment of hypoplastic left heart syndrome

OBJECTIVE

Hypoplastic left heart syndrome (HLHS) is one of the most serious congenital cardiac anomalies. Typically, it is managed with a series of 3 palliative operations or cardiac transplantation. Our goal was to quantify the inpatient resource burden of HLHS across multiple academic medical centers.

METHODS

The University HealthSystem Consortium is an alliance of 101 academic medical centers and 178 affiliated hospitals that share diagnostic, procedural, and financial data on all discharges. We examined inpatient resource use by patients with HLHS who underwent a staged palliative procedure or cardiac transplantation between 1998 and 2007.

RESULTS

Among 1941 neonates, stage 1 palliation (Norwood or Sano procedure) had a median length of stay (LOS) of 25 days and charges of $214,680. Stage 2 and stage 3 palliation (Glenn and Fontan procedures, respectively) had median LOS and charges of 8 days and $82,174 and 11 days and $79,549, respectively. Primary neonatal transplantation had an LOS of 87 days and charges of $582,920, and rescue transplantation required 36 days and $411,121. The median inpatient wait time for primary and rescue transplants was 42 and 6 days, respectively. Between 1998 and 2007, the LOS for stage 1 palliation increased from 16 to 28 days and inflation-adjusted charges increased from $122,309 to $280,909, largely because of increasing survival rates (57% in 1998 and 83% in 2007).

CONCLUSIONS

Patients with HLHS demand considerable inpatient resources, whether treated with the Norwood-Glenn-Fontan procedure pathway or cardiac transplantation. Improved survival rates have led to increased hospital stays and costs.

A comparison of prestorage WBC-reduced whole-blood-derived platelets and bedside-filtered whole-blood-derived platelets in autologous progenitor cell transplant

BACKGROUND

Prestorage WBC-reduced platelet concentrates (PCs) can be manufactured from platelet-rich plasma (PRP) by in-line filtration of PRP. There are few published data on the clinical use of these products, as compared to bedside-filtered pools of standard PCs (S-PCs) manufactured from PRP.

STUDY DESIGN AND METHODS

A prospective, randomized trial was conducted in autologous progenitor cell transplant patients requiring platelet transfusions with each patient as his or her own control who was given a pool of 5 units of WBC-reduced PCs and a pool of 6 units of S-PCs within a 3-hour period. The pools were characterized before transfusion for platelet and WBC content, P-selectin expression, and IL-8. The patients were monitored with platelet counts and vital signs and observed for reactions. Data were analyzed using Mann-Whitney U tests.

RESULTS

Thirty-three transfusions were administered to 13 patients. Median platelet content in the WBC-reduced PC pools was lower than that in the S-PC pools (3.3 vs. 4.0 x 10(11), p<0.01). Median WBC content was 4 to 5 log less in the WBC-reduced PC pools (2.5 x 10(4) vs. 4.6 x 10(8), p<0.01). Median IL-8 levels (pg/mL) were lower in the WBC-reduced PC pools (2 vs. 36, p<0.01). No differences were observed in CCI, but the median absolute increase after transfusion of the S-PC pools was higher (25 vs. 19 x 10(9)/L, p<0.01), which reflected the larger size of the S-PC pools. No overall differences in vital signs were recorded. Two reactions were observed, both in temporal association with the transfusion of pools of S-PCs.

CONCLUSIONS

A pool consisting of 5 units of WBC-reduced PCs gave a median platelet increment of 19 x 10(9) per L in these thrombocytopenic patients and has a median WBC content 1 to 2 log below the accepted threshold for primary alloimmunization or CMV transmission.

Seasonal migration and health care

This article examines health care use and issues among seasonal migrants in an urban setting in the Sunbelt. The study, based on a survey of 230 American and Canadian snowbirds in Phoenix, Arizona, complements previous research on health care use among Canadian snowbirds in Florida. Our results show that health care use among seasonal migrants in Phoenix is substantial, and it varies by citizenship (American vs. Canadian), age, number of winter visits, and length of winter stay. We argue that health care use is symptomatic of social and emotional attachments to the winter residence that develop and deepen over a period of years. Phoenix snowbirds view their lifestyles as healthy, they are adept in adjusting to health decrements, and the majority plan to continue spending time in both their summer and winter residences as long as their health permits.

Seasonal migration as a substitute for, or precursor to, permanent migration

Seasonal migration to national amenity areas is a major form of cyclical migration in the United States. This article examines conditions under which seasonal movement serves as a substitute for, or precursor to, permanent migration among winter visitors to recreational vehicle (RV) parks in the Phoenix, Arizona area. Ties to the home community, ties to the seasonal residence, demographic characteristics, and commitment to a mobile lifestyle are specified as determinants of expectations of moving to Phoenix on a permanent basis. The model is tested using survey data for a sample of 1,001 winter visitors in Phoenix RV parks. Results of a discriminant analysis indicate that place ties and position in the life cycle condition expectations of permanently migrating to a seasonal residence.

Determinants of short- and long-term mobility expectations for home owners and renters

Confusion about the role of residential satisfaction vis-à-vis structural factors in the mobility process stems from the failure to examine the determinants of mobility over varying time frames and housing tenures. Using survey data for a random sample of 580 Phoenix-area households, we test models of short-term (1 year) and long-term (5 years) mobility expectations for home owners and renters. The results show that residential satisfaction mediates the effects of structural variables on mobility expectations in the short term for home owners. In the long-term model for home owners and the short-term model for renters, the role of satisfaction as an intervening force declines in relative importance. Among renters, structural variables operate directly on long-term mobility expectations.