Rapid, Homogenous, B-Alkyl Suzuki-Miyaura Cross-Coupling of Boronic Esters.

A rapid, anhydrous Suzuki-Miyaura cross-coupling of alkylboronic esters with aryl halides is described. Parallel experimentation revealed that the combination of AntPhos, an oxaphosphole ligand, neopentyldiol alkylboronic esters, and potassium trimethylsilanolate (TMSOK) enables successful cross-coupling. In general, reactions proceed in under 1 h with good yields and high linear/branched (l/b) selectivities. Crucially, two literature examples which previously took >20 h to reach completion were accomplished in a fraction of the time with the method described herein. Mechanistic studies revealed that the reaction proceeds through a stereoretentive pathway and identified the boronic ester skeleton as a predominant pathway for deleterious protodehalogenation.

The teammate trial: Study design and rationale tacrolimus and everolimus against tacrolimus and MMF in pediatric heart transplantation using the major adverse transplant event (MATE) score.

BACKGROUND: Currently there are no immunosuppression regimens FDA-approved to prevent rejection in pediatric heart transplantation (HT). In recent years, everolimus (EVL) has emerged as a potential alternative to standard tacrolimus (TAC) as the primary immunosuppressant to prevent rejection that may also reduce the risk of cardiac allograft vasculopathy (CAV), chronic kidney disease (CKD) and cytomegalovirus (CMV) infection. However, the 2 regimens have never been compared head-to-head in a randomized trial. The study design and rationale are reviewed in light of the challenges inherent in rare disease research. METHODS: The TEAMMATE trial (IND 127980) is the first multicenter randomized clinical trial (RCT) in pediatric HT. The primary purpose is to evaluate the safety and efficacy of EVL and low-dose TAC (LD-TAC) compared to standard-dose TAC and mycophenolate mofetil (MMF). Children aged <21 years at HT were randomized (1:1 ratio) at 6 months post-HT to either regimen, and followed for 30 months. Children with recurrent rejection, multi-organ transplant recipients, and those with an estimated glomerular filtration rate (eGFR) <30 mL/min/1.73m2 were excluded. The primary efficacy hypothesis is that, compared to TAC/MMF, EVL/LD-TAC is more effective in preventing 3 MATEs: acute cellular rejection (ACR), CKD and CAV. The primary safety hypothesis is that EVL/LD-TAC does not have a higher cumulative burden of 6 MATEs (antibody mediated rejection [AMR], infection, and post-transplant lymphoproliferative disorder [PTLD] in addition to the 3 above). The primary endpoint is the MATE score, a composite, ordinal surrogate endpoint reflecting the frequency and severity of MATEs that is validated against graft loss. The study had a target sample size of 210 patients across 25 sites and is powered to demonstrate superior efficacy of EVL/LD-TAC. Trial enrollment is complete and participant follow-up will be completed in 2023. CONCLUSION: The TEAMMATE trial is the first multicenter RCT in pediatric HT. It is anticipated that the study will provide important information about the safety and efficacy of everolimus vs tacrolimus-based regimens and will provide valuable lessons into the design and conduct of future trials in pediatric HT.

Organ transplantation using COVID-19-positive deceased donors.

The COVID-19 pandemic has influenced organ transplantation decision making. Opinions regarding the utilization of coronavirus disease-2019 (COVID-19) donors are mixed. We hypothesize that COVID-19 infection of deceased solid organ transplant donors does not affect recipient survival. All deceased solid organ transplant donors with COVID-19 testing results from March 15, 2020 to September 30, 2021 were identified in the OPTN database. Donors were matched to recipients and stratified by the COVID-19 test result. Outcomes were assessed between groups. COVID-19 test results were available for 17 694 donors; 150 were positive. A total of 269 organs were transplanted from these donors, including 187 kidneys, 57 livers, 18 hearts, 5 kidney-pancreases, and 2 lungs. The median time from COVID-19 testing to organ recovery was 4 days for positive and 3 days for negative donors. Of these, there were 8 graft failures (3.0%) and 5 deaths (1.9%). Survival of patients receiving grafts from COVID-19-positive donors is equivalent to those receiving grafts from COVID-19-negative donors (30-day patient survival = 99.2% COVID-19 positive; 98.6% COVID-19 negative). Solid organ transplantation using deceased donors with positive COVID-19 results does not negatively affect early patient survival, though little information regarding donor COVID-19 organ involvement is known. While transplantation is feasible, more information regarding COVID-19-positive donor selection is needed.

Diversity of Dystrophin Gene Mutations and Disease Progression in a Contemporary Cohort of Duchenne Muscular Dystrophy.

Abnormal dystrophin production due to mutations in the dystrophin gene causes Duchenne Muscular Dystrophy (DMD). Cases demonstrate considerable genetic and disease progression variability. It is unclear if specific gene mutations are prognostic of outcomes in this population. We conducted a retrospective cohort study of DMD patients followed at 17 centers across the USA and Canada from 2005 to 2015 with goal of understanding the genetic variability of DMD and its impact on clinical outcomes. Cumulative incidence of clinically relevant outcomes was stratified by genetic mutation type, exon mutation location, and extent of exon deletion. Of 436 males with DMD, 324 (74.3%) underwent genetic testing. Deletions were the most common mutation type (256, 79%), followed by point mutations (45, 13.9%) and duplications (23, 7.1%). There were 131 combinations of mutations with most mutations located along exons 45 to 52. The number of exons deleted varied between 1 and 52 with a median of 3 exons deleted (IQR 1-6). Subjects with mutations starting at exon positions 40-54 had a later onset of arrhythmias occurring at median age 25 years (95% CI 18-∞), p = 0.01. Loss of ambulation occurred later at median age of 13 years (95% CI 12-15) in subjects with mutations that started between exons 55-79, p = 0.01. There was no association between mutation type or location and onset of cardiac dysfunction. We report the genetic variability in DMD and its association with timing of clinical outcomes. Genetic modifiers may explain some phenotypic variability.

Effects of universal critical CHD screening of neonates at a mid-sized California congenital cardiac surgery centre.

INTRODUCTION: CHD affects over 1 million children in the United States. Studies show decreased mortality from CHD with newborn cardiac screening. California began a screening programme on 1 July, 2013. We evaluated the effect of mandatory screening on surgical outcomes at Loma Linda University Children's Hospital since 1 July, 2013. METHODS: We evaluated all infants having congenital heart surgery at Loma Linda University Children's Hospital between 1 July, 2013 and 31 December, 2018. Primary target diagnoses include hypoplastic left heart syndrome, pulmonary atresia with intact ventricular septum, tetralogy of Fallot, total anomalous pulmonary venous return, transposition of the great arteries, tricuspid atresia, and truncus arteriosus. Secondary target diagnoses include aortic coarctation, double outlet right ventricle, Ebstein anomaly, interrupted aortic arch, and single ventricle. Patients were stratified by timing of diagnosis (pre-screen, screen positive, and screen negative). Primary end points were post-operative length of stay, operative mortality, absolute mortality, and actuarial survival. RESULTS: The cohort included 274 infants. Of these, 79% were diagnosed prior to screening (46% prenatally). Only 38% of those screened were positive, with 13% of the cohort having a "missed diagnosis." CONCLUSIONS: Primary targets were more likely to be diagnosed by screening (53%), while secondary targets were unlikely to be diagnosed by screening (10%) (p = 0.004). Outcomes such as length of stay, operative mortality, and actuarial survival were not different based on timing of diagnosis (p > 0.05). Despite late diagnosis, those not diagnosed until after screening did not have adverse outcomes.

The Effect of Infectious Complications During Ventricular Assist Device Use on Outcomes of Pediatric Heart Transplantation.

To describe the impact of infectious adverse events (IAEs) during ventricular assist device (VAD) support on graft loss, infection, and rejection after pediatric heart transplant (HT). Pedimacs data were linked to Pediatric Heart Transplant Society (PHTS) data for patients receiving a VAD followed by HT between September 2012 and December 2016. Linked patients were categorized into IAE on VAD (group A) and no IAE on VAD (group B). Infectious adverse event locations included nondevice, device (external or internal), and sepsis. Post-HT outcomes for analysis were graft loss, infection, and rejection. Time-dependent analysis included Kaplan-Meier and multiphase parametric hazard function analysis. We linked 207 patients (age 9.4 ± 6.3 years). Post-HT follow-up was 19.4 patient-months (<8 days-4.1 years). Group A included 42 patients (20%) with 62 IAEs. Group B included 165 patients without an IAE. Group A patients were younger (7.4 ± 6.1 vs. 9.5 ± 6.3 years; p = 0.03), waited longer for HT (5.3 ± 4.1 vs. 2.9 ± 2.5 months; p = 0.0005), and were hospitalized longer post-HT (42 ± 59 vs. 23 ± 22 days; p = 0.05). VAD-related IAEs were rare (N = 11). Groups A and B had similar freedom from first post-HT infection, rejection, and graft loss (all p > 0.1). However, patients with VAD-related IAE were somewhat more likely to experience rejection (p = 0.03) and graft loss (p = 0.01). Children with an IAE on VAD who survive to HT are younger, wait longer for HT, and remain hospitalized longer than those without an IAE on VAD. Overall, IAE on VAD did not impact post-HT outcomes, but VAD-related IAE may be associated with graft loss and rejection.

COVID-19 diagnosis and testing in pediatric heart transplant recipients.

Pediatric heart transplant recipients have been expected to be at higher risk of adverse events from developing COVID-19 infection. COVID-19 RNA PCR and antibody testing has been performed in our cohort of patients since March 15, 2020 and outcomes were reviewed. COVID-19 infection in our population of pediatric heart transplant recipients is common (21%), despite recommendations to avoid contact with others. Asymptomatic COVID-19 infection is common as well (55%). Despite the frequency of infection, COVID-19 is well tolerated in this population (5% admission from home; 0% mortality). A suppressed immune system does not significantly inhibit an antibody response in pediatric heart transplant recipients (>70% antibody seroconversion) and appears to persist, similar to those without transplantation (>90 days). Routine testing for COVID-19 via PCR and antibody testing enhances the ability to detect COVID-19 infection in asymptomatic patients and may help reduce unintended transmission to more susceptible individuals.

Fontan-associated plastic bronchitis waitlist and heart transplant outcomes: A PHTS analysis.

Plastic bronchitis is a rare post-Fontan complication with limited treatment options. Heart transplantation has evolved as a potential curative option, but outcomes have not been well-defined. This study aims to assess contemporary waitlist and post-transplant outcomes in patients with plastic bronchitis. All Fontan patients were identified in the PHTS database (2010 - 2018). Waitlist and post-transplant outcomes were compared between Fontan patients with and without plastic bronchitis. Competing outcomes and Kaplan-Meier analyses were used to assess the impact of plastic bronchitis on waitlist and post-transplant survival. A secondary analysis excluded those with PLE from the comparison cohort. Of 645 Fontan patients listed for heart transplant, 69 (11%) had plastic bronchitis. At listing, patients with plastic bronchitis were younger (8.9 vs 11.1 years, P = .02), but had few other differences in baseline characteristics. A fewer Fontan patients with plastic bronchitis were listed in the more recent era (46 [15.4%] in 2010-2014 vs 23 [6.6%] in 2015-2018, P < .01). Overall, there was no difference in waitlist (P = .30) or post-transplant (P = .66) survival for Fontan patients with and without plastic bronchitis. The results were similar after excluding patients with PLE. Contrary to prior reports, this relatively large series showed that plastic bronchitis did not have a negative impact on survival to or after heart transplantation in Fontan patients. Our study also found a 50% reduction in listing in the current era, which may indicate evolution in management of Fontan patients.

Implantable Cardioverter Defibrillator Use in Males with Duchenne Muscular Dystrophy and Severe Left Ventricular Dysfunction.

Duchenne muscular dystrophy (DMD) is characterized by myocardial fibrosis and left ventricular (LV) dysfunction. Implantable cardioverter defibrillator (ICD) use has not been characterized in this population but is considered for symptomatic patients with severe LV dysfunction (SLVD) receiving guideline-directed medical therapy (GDMT). We evaluated ICD utilization and efficacy in patients with DMD. Retrospective cohort study of DMD patients from 17 centers across North America between January 2, 2005 and December 31, 2015. ICD use and its effect on survival were evaluated in patients with SLVD defined as ejection fraction (EF) < 35% and/ or shortening fraction (SF) < 16% on final echocardiogram. SLVD was present in 57/436 (13.1%) patients, of which 12 (21.1%) died during the study period. Of these 12, (mean EF 20.9 ± 6.2% and SF 13.7 ± 7.2%), 8 received GDMT, 5 received steroids, and none received an ICD. ICDs were placed in 9/57 (15.8%) patients with SLVD (mean EF 31.2 ± 8.5% and SF 10.3 ± 4.9%) at a mean age of 20.4 ± 6.3 years; 8/9 received GDMT, 7 received steroids, and all were alive at study end; mean ICD duration was 36.1 ± 26.2 months. Nine ICDs were implanted at six different institutions, associated with two appropriate shocks for ventricular tachycardia in two patients, no inappropriate shocks, and one lead fracture. ICD use may be associated with improved survival and minimal complications in DMD cardiomyopathy with SLVD. However, inconsistent GDMT utilization may be a significant confounder. Future studies should define optimal indications for ICD implantation in patients with DMD cardiomyopathy.

Risk Factors for Cardiac and Non-cardiac Causes of Death in Males with Duchenne Muscular Dystrophy.

As survival and neuromuscular function in Duchenne muscular dystrophy (DMD) have improved with glucocorticoid (GC) therapy and ventilatory support, cardiac deaths are increasing. Little is known about risk factors for cardiac and non-cardiac causes of death in DMD. A multi-center retrospective cohort study of 408 males with DMD, followed from January 1, 2005 to December 31, 2015, was conducted to identify risk factors for death. Those dying of cardiac causes were compared to those dying of non-cardiac causes and to those alive at study end. There were 29 (7.1%) deaths at a median age of 19.5 (IQR: 16.9-24.6) years; 8 (27.6%) cardiac, and 21 non-cardiac. Those living were younger [14.9 (IQR: 11.0-19.1) years] than those dying of cardiac [18 (IQR 15.5-24) years, p = 0.03] and non-cardiac [19 (IQR: 16.5-23) years, p = 0.002] causes. GC use was lower for those dying of cardiac causes compared to those living [2/8 (25%) vs. 304/378 (80.4%), p = 0.001]. Last ejection fraction prior to death/study end was lower for those dying of cardiac causes compared to those living (37.5% ± 12.8 vs. 54.5% ± 10.8, p = 0.01) but not compared to those dying of non-cardiac causes (37.5% ± 12.8 vs. 41.2% ± 19.3, p = 0.58). In a large DMD cohort, approximately 30% of deaths were cardiac. Lack of GC use was associated with cardiac causes of death, while systolic dysfunction was associated with death from any cause. Further work is needed to ensure guideline adherence and to define optimal management of systolic dysfunction in males with DMD with hopes of extending survival.

Congenitally "Inverted" Pulmonary Valve in Tetralogy of Fallot: When Nature Falters.

A cyanotic neonate with tetralogy of Fallot was found to have a congenitally inverted pulmonary valve. Diagnosis was made via echocardiography and cardiac catheterization. The valve opened retrograde into the right ventricle, which allowed severe regurgitation and prevented anterograde flow. This report is the first description of this anomaly in medical literature. (Level of Difficulty: Intermediate.).

Elective left pulmonary artery embolisation for pulmonary arteriovenous malformations secondary to cavopulmonary anastomoses not responsive to heart transplantation: a case report.

A 10-year-old female with heterotaxy-asplenia and complex CHD developed pulmonary arteriovenous malformations with associated cyanosis after Fontan completion. She underwent orthotopic heart transplantation, but her pulmonary arteriovenous malformations persisted with progressive worsening cyanosis. Elective transcatheter left pulmonary artery embolisation was performed 2 years post-transplant, which successfully normalised her oxygen saturation without a significant increase in pulmonary artery pressure.

Transition from intravenous treprostinil to enteral selexipag in an infant with pulmonary arterial hypertension.

Selexipag is an enteral, selective prostacyclin IP receptor agonist approved for pulmonary hypertension in adults. There are few reports of its use in children and none in infants. We report the first transition of an infant (11.5 months, 8.6 kg) from intravenous treprostinil (40 ng/kg/minute) to enteral selexipag (400 mcg twice daily) with a good response and no adverse effects.

Use of advanced heart failure therapies in Duchenne muscular dystrophy.

BACKGROUND: As survival and neuromuscular function in Duchenne Muscular Dystrophy (DMD) improve with glucocorticoid therapy and respiratory advances, the proportion of cardiac deaths is increasing. Little is known about the use and outcomes of advanced heart failure (HF) therapies in this population. METHODS: A retrospective cohort study of 436 males with DMD was performed, from January 1, 2005-January 1, 2018, with the primary outcome being use of advanced HF therapies including: implantable cardioverter defibrillator (ICD), left ventricular assist device (LVAD), and heart transplantation (HTX). RESULTS: Nine subjects had an ICD placed, 2 of whom (22.2%) had appropriate shocks for ventricular tachycardia; 1 and 968 days after implant, and all of whom were alive at last follow-up; median 18 (IQR: 12.5-25.5) months from implant. Four subjects had a LVAD implanted with post-LVAD survival of 75% at 1 year; 2 remaining on support and 1 undergoing HTX. One subject was bridged to HTX with ICD and LVAD and was alive at last follow-up, 53 months after HTX. CONCLUSION: Advanced HF therapies may be used effectively in select subjects with DMD. Further studies are needed to better understand risk stratification for ICD use and optimal candidacy for LVAD implantation and HTX, with hopes of improving cardiac outcomes.

Primary Transplantation for Congenital Heart Disease in the Neonatal Period: Long-term Outcomes.

BACKGROUND: Primary transplantation was developed in the 1980s as an alternative therapy to palliative reconstruction of uncorrectable congenital heart disease. Although transplantation achieved more favorable results, its utilization has been limited by the availability of donor organs. This review examines the long-term outcomes of heart transplantation in neonates at our institution. METHODS: The institutional pediatric heart transplant database was queried for all neonatal heart transplants performed between 1985 and 2017. Follow-up was obtained from medical records and an annually administered questionnaire. Overall survival and time to development of complications were estimated using the Kaplan Meier method. Univariate and multivariate analyses were performed to identify independent predictors of survival. RESULTS: Heart transplantation was performed in 104 neonates. Median age was 17 days. Hypoplastic left heart syndrome (classic or variant) was the primary diagnosis in 77.8% of patients. Survival at 10 years and 25 years was 73.9% and 55.8%, respectively. At 20 years, freedom from allograft vasculopathy and lymphoproliferative disease was 72.0% and 81.9%, respectively. Freedom from re-transplantation was 81.4% at 20 years. Eight patients (7.6%) developed end-stage renal disease. By multivariate analysis, lower glomerular filtration rate and allograft vasculopathy were the only significant predictors of death. CONCLUSIONS: Neonatal heart transplantation remains a durable therapy with very acceptable long-term survival. Children transplanted in the newborn period have the potential to reach adulthood with minimal need for reintervention.

The landscape of cardiovascular care in pediatric cancer patients and survivors: a survey by the ACC Pediatric Cardio-Oncology Work Group.

OBJECTIVE: To enhance the understanding of cardiovascular care delivery in childhood cancer patients and survivors. STUDY DESIGN: A 20-question survey was created by the Pediatric Cardio-oncology Work Group of the American College of Cardiology (ACC) Cardio-oncology Section to assess the care, management, and surveillance tools utilized to manage pediatric/young adult cardio-oncology patients. The survey distribution was a collaborative effort between Cardio-oncology Section and membership of the Adult Congenital and Pediatric Cardiology Section (ACPC) of the ACC. RESULTS: Sixty-five individuals, all self-identified as physicians, responded to the survey. Most respondents (n = 58,89%) indicated childhood cancer patients are regularly screened prior to and during cancer therapy at their centers, predominantly by electrocardiogram (75%), standard echocardiogram (58%) and advanced echocardiogram (50%) (i.e. strain, stress echo). Evaluation by a cardiologist prior to/during therapy was reported by only 8(12%) respondents, as compared to post-therapy which was reported by 28 (43%, p < 0.01). The most common indications for referral to cardiology at pediatric centers were abnormal test results (n = 31,48%) and history of chemotherapy exposure (n = 27,42%). Of note, during post-treatment counseling, common cardiovascular risk-factors like blood pressure (31,48%), lipid control (22,34%), obesity & smoking (30,46%) and diet/exercise/weight loss (30,46%) were addressed by fewer respondents than was LV function (72%). CONCLUSIONS: The survey data demonstrates that pediatric cancer patients are being screened by EKG and/or imaging prior to/during therapy at most centers. Our data, however, highlight the potential for greater involvement of a cardiovascular specialist for pre-treatment evaluation process, and for more systematic cardiac risk factor counseling in posttreatment cancer survivors.

The importance of preconception and prenatal genetic evaluation in heart transplant individuals and fetal and postnatal cardiac monitoring in their offspring.

A 24-year-old woman with a history of idiopathic dilated cardiomyopathy status post heart transplant gave birth to a healthy term female infant. At 5 months of age, the infant was diagnosed with severe left ventricular dysfunction with an ejection fraction of 18% and moderate non-compaction of the left ventricle. She received a heart transplant at 7 months of age. Familial dilated cardiomyopathy was diagnosed. Genetic testing revealed a likely pathogenic variant in the TPM1 gene. Fetal cardiac screening is critical for offspring of heart transplant recipients, especially when the reason for transplant was cardiomyopathy. Early genetic consultation and counselling is necessary for all heart transplant recipients, preferably prenatally. Postnatal screening of offspring is essential at birth, at 3-month intervals until 1 year of age, and then annually until the risk for familial cardiomyopathy is assessed.

Cancer recurrence and mortality after pediatric heart transplantation for anthracycline cardiomyopathy: A report from the Pediatric Heart Transplant Study (PHTS) group.

We aimed to determine whether malignancy after pediatric HTx for ACM affects overall post-HTx survival. Patients <18y listed for HTx for ACM in the PHTS database between 1993 and 2014 were compared to those with DCM. A 2:1 matched DCM cohort was also compared. Wait-list and post-HTx survival, along with freedom from common HTx complications, were compared. Eighty subjects were listed due to ACM, whereas 1985 were listed for DCM. Although wait-list survival was higher in the ACM group, post-HTx survival was lower for the ACM cohort. Neither difference persisted in the matched cohort analysis. Primary cause of death in the ACM group was infection, which was higher than the DCM group. Malignancy rates were not different. All ACM malignancies were due to PTLD without primary cancer recurrence or SMN. Long-term graft survival after pediatric HTx for ACM is no different than for matched DCM peers, nor is there an increased risk of any malignancy. However, risk of infection and death from infection after HTx are higher in the ACM group. Further studies are needed to assess the effects of prior chemotherapy on susceptibility to infection in this group.

New-onset diabetes mellitus after heart transplantation in children - Incidence and risk factors.

Diabetes mellitus is a recognized complication of SOT in adults and is associated with decreased graft and patient survival. Little is known about NOD in pediatric HT recipients. We aimed to characterize the incidence and describe risk factors for development of NOD after HT in children. Children who developed diabetes after HT were identified from the OPTN database. Demographic and clinical data before and after transplant were compared between patients with and without NOD. A total of 2056 children were included, 56% were male, 54% were Caucasian, and 62% had cardiomyopathy prior to HT. NOD developed in 219 children (11%) after HT. The incidence of NOD was 2.4, 9.0, and 10.4% at one, five, and 10 yr after HT, respectively. Obesity (HR: 4.32), dialysis prior to transplant (HR: 2.38), African American race (HR: 1.86), transplant before year 2000 (HR: 1.82), female gender (HR: 1.68), and older age at transplant (HR: 1.28) were independent predictors of NOD. The major modifiable risk factor for NOD is obesity, imparting the maximum hazard. Improved surveillance for diabetes in high-risk patients and specific prevention and intervention strategies are imperative in this population.