BackgroundPercutaneous closure of patent ductus arteriosus (PDA) in term neonates is established, but data regarding outcomes in infants born very preterm (<32 weeks of gestation) are minimal, and no published criteria exist establishing a minimal weight of 4 kg as a suitable cutoff. We sought to analyze outcomes of percutaneous PDA occlusion in infants born very preterm and referred for PDA closure at weights <4 kg.Methods and ResultsRetrospective analysis (January 2005–January 2014) was done at a single pediatric center. Procedural successes and adverse events were recorded. Markers of respiratory status (need for mechanical ventilation) were determined, with comparisons made before and after catheterization. A total of 52 very preterm infants with a median procedural weight of 2.9 kg (range 1.2–3.9 kg) underwent attempted PDA closure. Twenty‐five percent (13/52) of infants were <2.5 kg. Successful device placement was achieved in 46/52 (88%) of infants. An adverse event occurred in 33% of cases, with an acute arterial injury the most common complication. We observed no association between weight at time of procedure and the risk of an adverse event. No deaths were attributable to the PDA closure. Compared to precatheterization trends, percutaneous PDA closure resulted in improved respiratory status, including less exposure to mechanical ventilation (mixed effects logistic model, P<0.01).ConclusionsAmong infants born very preterm, percutaneous PDA closure at weights <4 kg is generally safe and may improve respiratory health, but risk of arterial injury is noteworthy. Randomized clinical trials are needed to assess clinically relevant differences in outcomes following percutaneous PDA closure versus alternative (surgical ligation) management strategies.

We developed a tissue-engineered vascular graft (TEVG) for use in children and present results of a U.S. Food and Drug Administration (FDA)–approved clinical trial evaluating this graft in patients with single-ventricle cardiac anomalies. The TEVG was used as a Fontan conduit to connect the inferior vena cava and pulmonary artery, but a high incidence of graft narrowing manifested within the first 6 months, which was treated successfully with angioplasty. To elucidate mechanisms underlying this early stenosis, we used a data-informed, computational model to perform in silico parametric studies of TEVG development. The simulations predicted early stenosis as observed in our clinical trial but suggested further that such narrowing could reverse spontaneously through an inflammation-driven, mechano-mediated mechanism. We tested this unexpected, model-generated hypothesis by implanting TEVGs in an ovine inferior vena cava interposition graft model, which confirmed the prediction that TEVG stenosis resolved spontaneously and was typically well tolerated. These findings have important implications for our translational research because they suggest that angioplasty may be safely avoided in patients with asymptomatic early stenosis, although there will remain a need for appropriate medical monitoring. The simulations further predicted that the degree of reversible narrowing can be mitigated by altering the scaffold design to attenuate early inflammation and increase mechano-sensing by the synthetic cells, thus suggesting a new paradigm for optimizing next-generation TEVGs. We submit that there is considerable translational advantage to combined computational-experimental studies when designing cutting-edge technologies and their clinical management.

Background-Melody Transcatheter Pulmonary Valve (TPV) replacement therapy represents an important advance in congenital cardiovascular interventions. The off-label extension of the Melody TPV to patients with nonconduit outflow tracts (right ventricular outflow tract [RVOT]) has the potential to vastly expand the population of patients eligible to benefit from nonsurgical restoration of RVOT function. However, knowledge on the performance of the Melody TPV in this setting is limited. Methods and Results-This is a multicenter, retrospective review of the Melody TPV when placed in nonconduit RVOTs, in which at least a portion of the circumference was composed of native tissue. Five centers contributed data on 31 patients. The median age at implantation was 24 years (range, 7-66). At a median follow-up of 15 months, all patients were alive. No patient had greater than mild TPV insufficiency, and the median maximum instantaneous gradients across the RVOT was 23 mm Hg. Stent fracture occurred in 32%. Eight patients developed more than mild TPV obstruction, of whom 6 were associated with identified stent fracture. Three patients developed blood stream infections. There were 5 reinterventions in 3 patients, including 3 repeat TPV implantations and 2 TPV explantations. Conclusions-Melody TPV implantation is feasible in selected patients with RVOTs comprised solely or predominantly native tissue and has the potential to expand the population of patients eligible to benefit from nonsurgical restoration of RVOT function. In early follow-up, valve competency seems preserved. The dominant mechanism of valve dysfunction seems to be related to stent fracture with recurrent obstruction. Additional data are necessary to better understand how to safely expand TPV therapy to this population. (Circ Cardiovasc Interv. 2014;7:374-380.)Key Word: pulmonary valve

Motor skills and neurodevelopment in infants with hypoplastic left heart syndrome (HLHS) who have undergone Hybrid Stage I palliation is unknown. The purpose of this study is to assess early neurodevelopment in infants with HLHS after Hybrid Stage I palliation. Developmental assessment was performed in HLHS infants who underwent Hybrid Stage I palliation at 2 and 4 months of age using the Test of Infant Motor Performance, and at 6 months of age, prior to undergoing the second staged surgery, using the Bayley Scales of Infant and Toddler Development, 3rd edition (Bayley-III). Results were compared to healthy control subjects and norm-referenced data. The HLHS group scored between -1 and -2 standard deviations (SD) below the mean at 2 months of age (p = 0.002), and within -1 SD of the mean, at 4 months of age (p = 0.0019), on the TIMP. Compared to the control group, composite motor skills were significantly lower at 6 months of age on the Bayley-III in the HLHS group (p = 0.0489), however, not significant for cognitive (p = 0.29) or language (p = 0.68). Percentile rank motor scores were 17 ± 20 % in the HLHS group compared to 85 ± 12 % for the healthy age-matched control group. Infants with HLHS who undergo Hybrid Stage I palliation score lower on standardized motor skill tests compared to healthy age-matched controls and the norm-referenced population. This suggests that infants with HLHS have poorer motor skill performance than typically developing infants at 6 months of age.

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In this feasibility study of the Harmony transcatheter pulmonary valve device, there was high procedural success and safety, and favorable acute device performance.

The Melody valve can be implanted at 24 mm in the stenotic/regurgitant bioprosthetic pulmonary, tricuspid, and aortic valve, dysfunctional right ventricle to pulmonary artery conduit, and the native right ventricular outflow tract, whereas the valve remains competent with only mild regurgitation.

In a previous limb-girdle muscular dystrophy type 2D (LGMD2D) clinical trial, robust alpha-sarcoglycan gene expression was confirmed following intramuscular gene (SGCA) transfer. This paved the way for first-in-human isolated limb infusion (ILI) gene transfer trial to the lower limbs. Delivery of scAAVrh74 .tMCK.hSGCA via an intravascular route through the femoral artery predicted improved ambulation. This method was initially chosen to avoid safety concerns required for large systemic vascular delivery viral loads. ILI methods were adopted from the extensive chemotherapy experience for treatment of malignancies confined to the extremities. Six LGMD2D subjects were enrolled in a dose-ascending openlabel clinical trial. Safety of the procedure was initially assessed in the single limb of a non-ambulant affected adult at a dose of 1 • 10 12 vg/kg. Subsequently, ambulatory children (aged 8-13 years) were enrolled and dosed bilaterally with either 1 • 10 12 vg/kg/limb or 3 • 10 12 vg/kg/limb. The six-minute walk test (6MWT) served as the primary clinical outcome; secondary outcomes included muscle strength (maximum voluntary isometric force testing) and SGCA expression at 6 months. All ambulatory participants except one had pre-and post-treatment muscle biopsies. All four subjects biopsied had confirmed SGCA gene delivery by immunofluorescence, Western blot analysis (14-25% of normal), and vector genome copies (5.4 • 10 3 -7.7 • 10 4 vg/lg). Muscle strength in the knee extensors (assessed by force generation in kilograms) showed improvement in two subjects that correlated with an increase in fiber diameter post gene delivery. Six-minute walk times decreased or remained the same. Vascular delivery of AAVrh74.tMCK.hSGCA was effective at producing SGCA protein at low doses that correlated with vector copies and local functional improvement restricted to targeted muscles. Future trials will focus on systemic administration to enable targeting of proximal muscles to maximize clinical benefit.