The Dutch national paediatric heart transplantation programme: outcomes during a 23-year period.

BACKGROUND: Since 1998, there has been a national programme for paediatric heart transplantations (HT) in the Netherlands. In this study, we investigated waiting list mortality, survival post-HT, the incidence of common complications, and the patients' functional status during follow-up. METHODS: All children listed for HT from 1998 until October 2020 were included. Follow-up lasted until 1 January 2021. Data were collected from the patient charts. Survival, post-operative complications as well as the functional status (Karnofsky/Lansky scale) at the end of follow-up were measured. RESULTS: In total, 87 patients were listed for HT, of whom 19 (22%) died while on the waiting list. Four patients were removed from the waiting list and 64 (74%) underwent transplantation. Median recipient age at HT was 12.0 (IQR 7.2-14.4) years old; 55% were female. One-, 5­, and 10-year survival post-HT was 97%, 95%, and 88%, respectively. Common transplant-related complications were rejections (50%), Epstein-Barr virus infections (31%), cytomegalovirus infections (25%), post-transplant lymphoproliferative disease (13%), and cardiac allograft vasculopathy (13%). The median functional score (Karnofsky/Lansky scale) was 100 (IQR 90-100). CONCLUSION: Children who undergo HT have an excellent survival rate up to 10 years post-HT. Even though complications post-HT are common, the functional status of most patients is excellent. Waiting list mortality is high, demonstrating that donor availability for this vulnerable patient group remains a major limitation for further improvement of outcome.

The First Evaluation of Remote Magnetic Navigation-Guided Pediatric Ventricular Arrhythmia Ablation.

Catheter ablation (CA) is an important treatment option for ventricular arrhythmias (VA) in pediatric cardiology. Currently, various CA techniques are available, including remote magnetic navigation (RMN)-guided radiofrequency (RF) ablation. However, no studies evaluate RMN-guided ablative therapy outcomes in children with VA yet. This study aimed to compare procedural and long-term outcomes between RMN-guided and manual (MAN)-guided VA ablation in children. This single-center, retrospective study included all CA procedures for VA performed in children with or without structural heart disease from 2008 until 2020. Two study groups were defined by CA technique: RMN or MAN. Primary outcome was recurrence of VA. Baseline clinical, procedural and safety data were also evaluated. This study included 22 patients, who underwent 30 procedures, with a median age of 15 (IQR 14-17; range 1-17) years and a mean weight of 57 ± 20 kg. In total, 14 procedures were performed using RMN and 16 using MAN (22 first and 8 redo procedures). Regarding first procedures, recurrence rates were significantly lower in RMN compared to MAN (20% versus 67%, P = 0.029), at a mean follow-up of 5.2 ± 3.0 years. Moreover, fluoroscopy dosages were significantly lower in RMN compared to MAN [20 (IQR 14-54) versus 48 (IQR 38-62) mGy, P = 0.043]. In total, 20 patients (91%) were free of VA following their final ablation procedure. This is the first study to investigate the use of RMN in pediatric VA ablation. RMN showed improved outcomes compared to MAN, resulting in lower VA recurrence and reduced fluoroscopy exposure.

"Absent" unilateral pulmonary arteries aren't absent, but disconnected. Review of the current literature based on 4 cases.

BACKGROUND: Disconnected unilateral pulmonary arteries are frequently misdiagnosed as "absent". They typically arise from the base of the innominate artery and are fed by an aberrant arterial duct. If diagnosed early enough, they can be reconnected with catheter techniques even after closure of this aberrant duct. Consecutive surgical anatomical correction at a later stage is possible. METHODS: Four cases illustrate the anatomical findings on computed tomography and angiography, all show an outpouching at the base of the brachiocephalic artery. RESULTS: The therapeutic approach consisted of stenting of the aberrant ductus and consecutive surgery. In the oldest patient, 13 years, such an approach was impossible. CONCLUSION: If identified early in life, disconnected pulmonary arteries can be recruited with catheter techniques, and reconnected surgically at a later stage. It is not yet known if this approach prevents pulmonary damage, which is frequently seen in older untreated patients.

Reconstruction of the Aortic Arch in Neonates and Infants: The Importance of Patch Material.

OBJECTIVES: Restenosis after aortic arch reconstruction is a known complication in neonates and infants. Homograft is the most commonly used patch material for aortic arch reconstructions in our center. Since 2014, tissue-engineered bovine pericardium (CardioCel) has been used as an alternative. The aim of our study was to determine whether the choice of material affected the development of restenosis in these patients. METHODS: Data of all neonates and infants who underwent aortic arch reconstruction with the use of any patch material between 2005 and 2016 were analyzed. Restenosis was defined by the need for reintervention, either percutaneous or surgical. RESULTS: Forty-one patients underwent aortic arch repair. Excluding the 30-day mortality, 36 patients represented the study population. At primary repair, the aortic arch was reconstructed with homograft (n = 26) or CardioCel (n = 10). Restenosis was documented during the first year of life in 13 patients: Six (23%) patients in the homograft group and seven (70%) patients in the CardioCel group (P = .01). In the homograft group, the median time from operation to first intervention for restenosis was 22.0 (range: 14-32) weeks, as compared to 14.0 (range: 7-21) weeks in the CardioCel group (P = .04). CONCLUSION: We conclude that choice of patch material is likely to be an important determinant for the risk of restenosis needing reintervention following reconstruction of the aortic arch in neonates and infants.

Pediatric Ventricular Assist Device Support in the Netherlands.

BACKGROUND: This study aimed to evaluate the changes in heart transplantation (HTx) waiting list mortality following the introduction of the Berlin Heart EXCOR (BH EXCOR) in the Netherlands, as well as the occurrence of adverse events in these children. METHODS: A retrospective, single-center study was conducted including all pediatric patients (≤18 years) awaiting HTx. Patients were grouped in two eras based on availability of the BH EXCOR in our center, era I (1998-2006; not available) and era II (2007 to July 31, 2018; available). RESULTS: In total, 87 patients were included, 15 in era I and 72 in era II. Extracorporeal membrane oxygenator support was required in 1 (7%) patient in era I and in 13 (18%) patients in era II. Overall mortality (7/15 in era I vs 16/72 in era II; 47% vs 22%, P = .06) and transplantation rates (8/15 in era I vs 47/72 in era II; 53% vs 65%, P = .39) did not differ significantly. Eleven (39%) patients of the pediatric ventricular assist device (VAD) population died, with the predominant cause being cerebrovascular accidents (CVAs) in eight (29%) patients. Furthermore, 14 (50%) of the pediatric VAD patients survived to transplantation. Adverse events most frequently occurring in VAD patients included CVA in 14 (50%), mostly (68%) within 30 days after VAD implantation, and bleeding requiring rethoracotomy in 14 (50%), all within 30 days after VAD implantation. CONCLUSIONS: The introduction of the BH EXCOR has positively impacted the survival of pediatric patients with end-stage heart failure in our center. The predominant cause of death changed from end-stage heart failure in era I to CVA in era II. We emphasize the need for large prospective registry-based studies.

Clinical outcomes of paediatric patients supported by the Berlin Heart EXCOR: a systematic review.

Ventricular assist devices (VADs) are widely accepted as therapy to bridge children to heart transplantation. We provide a systematic review of the current state of clinical outcomes in children after paediatric VAD support by the Berlin Heart EXCOR (BH EXCOR) device. A systematic literature search was performed in April 2018. Studies reporting clinical outcomes in at least 15 children supported by a BH EXCOR VAD were included. Additionally, we focused on outcomes in small children and compared outcomes of children supported by a left ventricular assist device (LVAD) versus children supported by a biventricular assist device (BiVAD). Eighteen publications fulfilled the inclusion criteria and were included in this systematic review. Mortality rates ranged from 6.3% [confidence interval (CI) 0.0-18.1%] to 38.9% (2.8-75.0%) while transplantation rates ranged from 37.0% (CI 18.8-55.2%) to 72.5% (CI 63.9-81.2%) and successful weaning rates from 0.0% to 20.7% (CI 6.0-35.5%). In children under 1 year of age, mortality rates ranged from 20.0% to 55.5% and transplantation rates ranged from 0.0% to 62.5%. BiVAD support seemed to result in worse clinical outcomes than LVAD support. Incidence of stroke ranged from 5.0% to 47.0% in all children supported with the BH EXCOR. Although a high incidence of adverse events such as stroke and pump thrombosis is reported, VAD support should be considered in children with end-stage heart failure awaiting heart transplantation. Further research is warranted, especially on optimal timing of device implantation and anticoagulation regimens.

Mechanical circulatory support in the Dutch National Paediatric Heart Transplantation Programme.

OBJECTIVES: Mechanical circulatory support (MCS) with a ventricular assist device (VAD) as a bridge to heart transplantation (HTx) or recovery may improve outcome in children with terminal heart failure. We report our experience with MCS in children eligible for HTx and its effect on waiting list mortality. METHODS: Retrospective single-centre cohort study, National Paediatric HTx Programme including all children eligible for HTx, since the introduction of MCS-VAD in 2006. RESULTS: A total of 43 patients were eligible for HTx, median age 11.7 years [Inter Quartile Range (IQR) 3.0-14.7]. In 18 patients, (42%) a VAD was implanted, 11 (61%) survived to HTx (n = 9) or recovery (n = 2). Techniques and devices used were left ventricular assist device (n = 16, 89%), in 4 cases preceded by extracorporeal membrane oxygenation (ECMO), and biventricular assist device (n = 2, 11%), both preceded by ECMO. In the VAD group, median time to death (n = 7) was 18 days (IQR 7-75), median time to HTx (n = 9) 66 days (IQR 33-223) and 2 patients recovered after 30 and 308 days. The main cause of death on MCS was neurological injury in 4 patients (22%) and systemic thrombo-embolic events in 2 (11%). The most common serious adverse events included confirmed thrombus requiring pump replacement (in 11 patients, 61%) and pericardial effusion leading to rethoracotomy (in 5 patients, 28%). Compared with the era before MCS (1998-2006), waiting list mortality decreased from 44 to 21%, and is now mainly related to complications of VAD support. CONCLUSIONS: Since the introduction of MCS-VAD, waiting list mortality halved and more children with end-stage heart failure survived to heart transplantation, thus improving outcome. Although there is substantial mortality and morbidity, overall mortality decreases, making MCS-VAD an essential therapeutic tool. The need for donor organs remains critically urgent.

ACTA2 mutation with childhood cardiovascular, autonomic and brain anomalies and severe outcome.

Thoracic aortic aneurysm and dissection (TAAD) are associated with connective tissue disorders like Marfan syndrome and Loeys-Dietz syndrome, caused by mutations in the fibrillin-1, the TGFß-receptor 1- and -2 genes, the SMAD3 and TGFß2 genes, but have also been ascribed to ACTA2 gene mutations in adults, spread throughout the gene. We report on a novel de novo c.535C>T in exon 6 leading to p.R179C aminoacid substitution in ACTA2 in a toddler girl with primary pulmonary hypertension, persistent ductus arteriosus, extensive cerebral white matter lesions, fixed dilated pupils, intestinal malrotation, and hypotonic bladder. Recently, de novo ACTA2 R179H substitutions have been associated with a similar phenotype and additional cerebral developmental defects including underdeveloped corpus callosum and vermis hypoplasia in a single patient. The patient here shows previously undescribed abnormal lobulation of the frontal lobes and position of the gyrus cinguli and rostral dysplasis of the corpus callosum; she died at the age of 3 years during surgery due to vascular fragility and rupture of the ductus arteriosus. Altogether these observations support a role of ACTA2 in brain development, especially related to the arginine at position 179. Although all previously reported patients with R179H substitution successfully underwent the same surgery at younger ages, the severe outcome of our patient warns against the devastating effects of the R179C substitution on vasculature.

Results of balloon dilatation of stenotic homografts in pulmonary position in children and young adults.

OBJECTIVES: To evaluate the results of balloon dilatation of stenotic homografts in children, adolescents, and young adults and to identify factors that might influence or predict the effect of the dilatation. BACKGROUND: Homografts are widely used in congenital cardiac surgery; however, the longevity remains a problem mostly because of stenosis in the homograft. The effect of treatment by balloon dilatation is unclear. METHODS: In a retrospective study, the effect of balloon dilatation was determined by the percentage of reduction of the peak systolic pressure gradient over the homograft during catheterisation and the postponement of re-intervention or replacement of the homograft in months. Successful dilatations - defined in this study as a reduction of more than 33% and postponement of more than 18 months - were compared with unsuccessful dilatations in search of factors influencing or predicting the results. RESULTS: The mean reduction of the peak systolic pressure gradient was 30% in 40 procedures. Re-intervention or replacement of the homograft was postponed by a mean of 19 months. In all, 14 balloon dilatations (35%) were successful; the mean reduction was 49% and the mean postponement was 34 months. The time since homograft implantation, the presence of calcification, the homograft/balloon ratio, and the pressure applied during dilatation all tended to correlate with outcome, but were not statistically significant. CONCLUSIONS: Balloon dilatation is able to reduce the peak systolic pressure gradient over homografts in a subgroup of patients and can be of clinical significance to postpone re-intervention or pulmonary valve replacement.

Successful treatment of congenital acute myeloid leukemia (AML-M6) in a premature infant.

Congenital acute myeloid leukemia (AML), and especially AML-M6 is a rare disease with a poor prognosis. Moreover, reports of treatment outcome of congenital AML-M6 in premature infants are not available. We report the first treated case of congenital AML-M6 in a premature girl, who received a full AML protocol. She presented with blueberry-muffin spots, anemia, high white blood cell count, and serious cardiopulmonary distress. Peripheral blood smears showed AML-M6 blasts. After treatment with a sequential low-dose cytarabine after birth and full-dose AML treatment according to the MRC-12 protocol at the age of 2 months, she now is in continuous complete remission for 4 years.