Survival does not differ by annual center transplant volume-A Pediatric Heart Transplant Society Registry study.

BACKGROUND: There are conflicting data regarding the relationship between center volume and outcomes in pediatric heart transplantation. Previous studies have not fully accounted for differences in case mix, particularly in high-risk congenital heart disease (CHD) groups. We aimed to evaluate the relationship between center volume and outcomes using the Pediatric Heart Transplant Society (PHTS) Registry and explore how case mix may affect outcomes. METHODS: A retrospective cohort study of all pediatric patients in the PHTS Registry who received a heart transplant from 2009 to 2018 was performed. Centers were divided into 5 groups based on average yearly transplant volume. The primary outcome was time to death or graft loss and outcomes were compared using Kaplan-Meier analysis. RESULTS: There were 4583 cases among 55 centers included. There was no difference in time to death or graft loss by center volume in the entire cohort (p = .75), in patients with CHD (p = .79) or in patients with cardiomyopathy (p = .23). There was also no difference in time to death or graft loss by center size in patients undergoing transplant after Norwood, Glenn or Fontan (log rank p = .17, p = .31, and p = .10 respectively). There was a statistically significant difference in outcomes by center size in the positive crossmatch group (p < .0001), though no discernible pattern related to high or low center volume. CONCLUSIONS: Outcomes are similar among transplant centers of all sizes, including for high-risk patient groups with CHD. Future work is needed to understand how patient-specific risk factors may vary among centers of various sizes and whether this influences patient outcomes.

Clinical, immunohistochemical, and genetic characterization of splice-altering biallelic DES variants: Therapeutic implications.

Pathogenic variants in the DES gene clinically manifest as progressive skeletal muscle weakness, cardiomyopathy with associated severe arrhythmias, and respiratory insufficiency, and are collectively known as desminopathies. While most DES pathogenic variants act via a dominant mechanism, recessively acting variants have also been reported. Currently, there are no effective therapeutic interventions for desminopathies of any type. Here, we report an affected individual with rapidly progressive dilated cardiomyopathy, requiring heart transplantation at age 13 years, in the setting of childhood-onset skeletal muscle weakness. We identified biallelic DES variants (c.640-13 T>A and c.1288+1 G>A) and show aberrant DES gene splicing in the affected individual's muscle. Through the generation of an inducible lentiviral system, we transdifferentiated fibroblast cultures derived from the affected individual into myoblasts and validated this system using RNA sequencing. We tested rationally designed, custom antisense oligonucleotides to screen for splice correction in these transdifferentiated cells and a functional minigene splicing assay. However, rather than correctly redirecting splicing, we found them to induce undesired exon skipping. Our results indicate that, while an individual precision-based molecular therapeutic approach to splice-altering pathogenic variants is promising, careful preclinical testing is imperative for each novel variant to test the feasibility of this type of approach for translation.

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.

Neonatal Myocardial Infarction: A Proposed Algorithm for Coronary Arterial Thrombus Management.

BACKGROUND: Neonatal myocardial infarction is rare and is associated with a high mortality of 40% to 50%. We report our experience with neonatal myocardial infarction, including presentation, management, outcomes, and our current patient management algorithm. METHODS: We reviewed all infants admitted with a diagnosis of coronary artery thrombosis, coronary ischemia, or myocardial infarction between January 2015 and May 2021. RESULTS: We identified 21 patients (median age, 1 [interquartile range (IQR), 0.25-9.00] day; weight, 3.2 [IQR, 2.9-3.7] kg). Presentation included respiratory distress (16), shock (3), and murmur (2). Regional wall motion abnormalities by echocardiogram were a key criterion for diagnosis and were present in all 21 with varying degrees of depressed left ventricular function (severe [8], moderate [6], mild [2], and low normal [5]). Ejection fraction ranged from 20% to 54% (median, 43% [IQR, 34%-51%]). Mitral regurgitation was present in 19 (90%), left atrial dilation in 15 (71%), and pulmonary hypertension in 18 (86%). ECG was abnormal in 19 (90%). Median troponin I was 0.18 (IQR, 0.12-0.56) ng/mL. Median BNP (B-type natriuretic peptide) was 2100 (IQR, 924-2325) pg/mL. Seventeen had documented coronary thrombosis by cardiac catheterization. Seventeen (81%) were treated with intracoronary tPA (tissue-type plasminogen activator) followed by systemic heparin, AT (antithrombin), and intravenous nitroglycerin, and 4 (19%) were treated with systemic heparin, AT, and intravenous nitroglycerin alone. Nineteen of 21 recovered. One died (also had infradiaphragmatic total anomalous pulmonary venous return). One patient required a ventricular assist device and later underwent heart transplant; this patient was diagnosed late at 5 weeks of age and did not respond to tPA. Nineteen of 21 (90%) regained normal left ventricular function (ejection fraction, 60%-74%; mean, 65% [IQR, 61%-67%]) at latest follow-up (median, 6.8 [IQR, 3.58-14.72] months). Two of 21 (10%) had residual trivial mitral regurgitation. After analysis of these results, we present our current algorithm, which developed and matured over time, to manage neonatal myocardial infarction. CONCLUSIONS: We experienced a lower mortality rate for infants with neonatal infarction than that reported in the literature. We propose a post hoc algorithm that may lead to improvement in patient outcomes following coronary artery thrombus.

Heart Transplantation of a Preterm Infant With HLHS.

A 33-week gestation, 1.75-kg female infant with mitral stenosis/aortic atresia variant of hypoplastic left heart syndrome and severe ventriculo-coronary connections underwent surgical septectomy and bilateral pulmonary artery banding at five weeks of age (2.10 kg). After separation from bypass, she developed hemodynamic instability requiring venoarterial extracorporeal membrane oxygenation support. She was listed for heart transplantation and transplanted after three days of support with an oversized heart (4.7:1 donor-recipient weight ratio).

Evaluation of Fontan liver disease: Correlation of transjugular liver biopsy with magnetic resonance and hemodynamics.

INTRODUCTION: Liver fibrosis and cirrhosis are late complications in Fontan palliation. Liver biopsy is the gold standard. The goal of this study is to correlate transjugular liver biopsy (TJLB) in the setting of Fontan palliation with noninvasive testing and hemodynamics. METHODS: Between August 2014 and July 2017, 49 Fontan patients underwent TJLB. All the patients had hemodynamic evaluation, 28 patients had MRE (magnetic resonance elastography) and 40 patients had cardiopulmonary exercise test. Histologic liver fibrosis was quantitated using traditional histologic scoring systems and a modified Ishak congestive hepatic fibrosis score. RESULTS: Median age 17.8 years, median time since Fontan 15.2 years. Primary diagnosis and Fontan type were variables, but predominantly LV morphology (30/49), lateral tunnel Fontan (29/49), originally fenestrated (37/49), and 11/49 had a pacemaker. Histologic fibrosis correlated with MRE (R = 0.62, P ≤ .001). Histologic fibrosis and MRE correlated with Fontan pressure (R = 0.38, P = .008 & R = 0.59, P ≤ .001). Morphology of the single ventricle did not correlate with liver fibrosis. The presence of a fenestration resulted in a higher cardiac index (P = .026) but did not resulted in lower liver fibrosis (P = .64). CONCLUSION: Noninvasive tests, such as MRE, may be suitable for longitudinal follow-up in patients with single ventricle physiology. Our data suggest that there is reasonable correlation of MRE liver stiffness with biopsy scoring systems and Fontan pressures. We demonstrated the feasibility of TJLB in the setting of Fontan palliation and demonstrated its correlation with noninvasive measures particularly MRE. We recommend selective use of TJLB when MRE score is >5 KPa or when there are other clinical signs of cirrhosis.

Perforation and right ventricular outflow tract stenting: Alternative palliation for infants with pulmonary atresia/ventricular septal defect.

BACKGROUND: Right ventricular outflow tract (RVOT) stents have been used as palliation in patients with severe tetralogy of Fallot (TOF). Radiofrequency perforation of the RVOT has also been described in patients with pulmonary atresia (PA)/ventricular septal defect (VSD). However, RVOT stenting in conjunction with radiofrequency perforation as a means for establishing reliable pulmonary blood flow in patients with PA/VSD has not previously been reported. OBJECTIVES: Our aim is to report our experience with using perforation of plate-like pulmonary valve atresia combined with stenting of RVOT as an alternative and equally efficacious intervention for infants with PA/VSD, as compared to a surgical pulmonary artery shunt (SPS). METHODS: A retrospective review of patients with PA/VSD at our institution from Jan 2006 to October 2015 was performed. RESULTS: Twenty-seven patients received palliation for PA/VSD. Five (median 2.5 kg, 2.1-4.1 kg) underwent RVOT stenting and 22 (3.5 kg, 2.1-4.6 kg) underwent surgical SPS. Of the patients who received an RVOT stent, 3 underwent guidewire perforation and balloon dilation of the plate-like pulmonary valve, and 2 underwent radiofrequency perforation of the pulmonary plate, followed by balloon dilation. Postprocedure saturations averaged 93% in the stent group and 89% in the shunt group. One of the patients who underwent RVOT stenting required additional stenting of the PDA for isolation of the LPA, but none required re-intervention. Four patients in the SPS cohort required re-intervention (18%). Two required stenting of the shunt, and 2 required surgical revision of the shunt. There was one death in the stent group, however this was secondary to withdrawal of support given an underlying genetic diagnosis (trisomy 13). There was one fatality in the SPS cohort prior to hospital discharge. CONCLUSIONS: Perforation followed by RVOT stenting may be a safe and effective alternative to surgical SPS in infants with PA/VSD.

Outcome of antibody-mediated rejection compared to acute cellular rejection after pediatric heart transplantation.

Outcomes of ACR after pediatric HTx have been well described, but less has been reported on outcomes of AMR. We compared the clinical characteristics and cardiovascular outcomes (composite end-point of death, retransplantation, or allograft vasculopathy) of pediatric HTx recipients with AMR, ACR, and no rejection in a retrospective single-center study of 104 recipients. Twenty were treated for AMR; 15 were treated for ACR. Recipients with AMR had an increased frequency of congenital heart disease (90% vs ACR 67% vs no rejection 59%, P = .03), homograft (68% vs 7% vs 18%, P < .001), HLA sensitization (45% vs 13% vs 13%, P = .008), and positive cross-match (30% vs 7% vs 9%, P = .046). AMR caused hemodynamic compromise more often than ACR (39% vs 4%, P = .02). AMR recipients had worse cardiovascular outcome than recipients with ACR or no rejection (40% vs 20% vs 8.6%, P = .003). In bivariate Cox analysis, AMR (HR 4.1, CI 1.4-12.0, P = .009) and ischemic time (HR 1.6, CI 1.1-2.3, P = .02) were associated with worse cardiovascular outcome; ACR was not. In summary, pediatric HTx recipients who develop AMR have worse cardiovascular outcome than recipients who develop only ACR or experience no rejection at all.

Transcatheter stenting of the systemic-to-pulmonary artery shunt: A 7-year experience from a single tertiary center.

BACKGROUND: Systemic-to-pulmonary artery shunt (SPS) dysfunction can be deleterious in shunt dependent patients and traditionally have undergone surgical revision. Data on transcatheter stenting of SPS is limited. We sought to evaluate feasibility, safety and outcomes of stenting SPS. METHODS: Retrospective review of all patients who underwent transcatheter SPS stenting from 1/2006 to 12/2013. RESULTS: Of 229 surgically implanted SPS, 25 transcatheter stent interventions were performed in 22 patients. The majority had pulmonary atresia (n = 9) or HLHS (n = 10). Their median age was 4 ms (range 10 days to 4 years) and median weight 4.9 kg (range 3-14). Nine had a central and 15 had a BT shunt with a median shunt size of 3.75 mm (range 3-6). The interval from shunt placement to intervention was 1.9 ms (range 4 days-3.8 years). The indication for intervention was increasing cyanosis in10 patients and delaying final repair in 9. Two patients were on ECMO at the time of intervention. The median shunt diameter increased from 2.3 to 4.1 mm and oxygen saturation from 72 to 85% (P < 0.001). No intra-procedural complications were encountered. One patient died from aspiration (autopsy demonstrated a patent shunt), 13 progressed to repair or next stage, 6 remain palliated with shunts as they are deemed unfit for the next stage and 2 are awaiting surgery. CONCLUSIONS: Stenting of systemic to pulmonary artery shunt is a safe and effective procedure and avoids surgical re-intervention. It can be performed both as a rescue procedure in patients with acute shunt occlusion and as an elective procedure to palliate patients not yet suitable for subsequent corrective or staged repair.

Comparison of ductal stenting versus surgical shunts for palliation of patients with pulmonary atresia and intact ventricular septum.

OBJECTIVES: We sought to compare ductal stenting (DS) to systemic-pulmonary artery shunt (SPS) in a contemporary cohort of patients having pulmonary atresia with intact ventricular septum (PAIVS). BACKGROUND: Alternative palliative strategies (interventional versus surgical) are currently available for initial palliation of ductal dependent patients with various forms of congenital heart disease. There is little data available to guide strategy selection. METHODS: A retrospective review of patients with PAIVS at our institution from Jan 2006 to Dec 2013 was performed. Demographic, echocardiographic, procedural, and follow-up data were reviewed and analyzed. RESULTS: Twenty-nine patients were identified. Thirteen underwent DS and 16 underwent SPS. In the DS group, 6 had radiofrequency perforation of the pulmonary valve, and 12 underwent balloon pulmonary valvuloplasty (BPV) prior to DS. SPS was performed after perforation of the pulmonary valve in 1 patient and after BPV in 4 patients. Procedural success was 92.8% in the DS group versus 93.3% in the SPS group. In the DS group, one patient required emergency shunting due to intra-procedural ductal spasm. In the SPS group there was one procedure related death, and there were six significant procedure-related complications. Five patients required re-interventions prior to hospital discharge. The median length of hospital stay for the DS versus SPS group was 10 versus 23 days, respectively (P < 0.05). Post discharge, there were seven reinterventions in the DS group and two reinterventions in the SPS group. CONCLUSIONS: DS may provide a safe and effective alternative to SPS in selected patients with PAIVS.