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Current leadless pacemaker (LP) systems, which have been developed and used in patients with normal cardiac anatomy, are rare and technically even more challenging to implant in patients with congenital heart diseases, especially with univentricular physiology and Fontan palliation. We report two cases of percutaneous LP implantation in an adult and a child, respectively, highlighting the unconventional approaches, different challenges, and use of multimodality imaging in patients who underwent a Fontan operation., Competing Interests: The authors report no conflicts of interest for the published content. No funding information was provided., (Copyright: © 2024 Innovations in Cardiac Rhythm Management.)

Background: Transverse aortic arch obstruction is a challenging lesion for which stent implantation provides a potentially important alternate therapy. The objectives were to evaluate the technical, procedural, and medium-to-long-term clinical outcomes of percutaneous stent implantation of transverse aortic arch obstruction., Methods: This is a retrospective, multicenter study of transverse aortic arch stent implantation. Univariable and multivariable analyses were performed., Results: Index catheterization included 187 stent implants in 146 patients. The median age is 14.3 years (interquartile range, 9.3-19), weight is 53 kg (30-69), and follow-up is 53 months (12-120). The most common stent design was open cell (n=90, 48%). Stents overlapped 142 arch vessels (37 carotid arteries) in 118 (81%) cases. Technical and procedural success rates were 100% and 88%, respectively. Lower weight ( P =0.018), body surface area ( P =0.013), and minimum-to-descending aortic diameter ratio ( P <0.001) were associated with higher baseline aortic gradient. The residual gradient was inversely associated with implant and final dilation diameters ( P <0.001). The combined incidence of aortic injury and stent-related complications was 14%. There were no reports of abnormal brain scans or stroke. Blood pressure cuff gradient, echocardiographic arch velocity, and hypertension rates improved within 1-year follow-up with increased antihypertensive medication use. Reintervention was reported in 60 (41%) patients at a median of 84 (22-148) months to first reintervention. On multivariable logistic regression, residual aortic gradient >10 mm Hg was associated with increased odds of reintervention at all time points when controlling for each final dilation diameter, weight, and minimum-to-descending aortic diameter ratio., Conclusions: Transverse aortic arch stent implantation has high rates of technical, procedural, and medium-to-long-term clinical success. Aortic gradient >10 mm Hg is associated with increased odds of reintervention at 1-year and most recent follow-ups. Open cell stent design was frequently used for its advantages in conformability, perfusion of arch vessels, low fracture rate, and the ability to perform effective angioplasty of side cells., Competing Interests: Dr Armstrong is a consultant for Abbott, Medtronic, Edwards Lifesciences, Cook Medical, Starlight Cardiovascular, and B. Braun Interventional Systems and received research support from Edwards Lifesciences, Renata Medical, and atHeart Medical. Dr Boe is a consultant at Abbott and Medtronic. Dr Cheatham is a consultant, a proctor, and a principal investigator at Medtronic; a consultant at NuMED; a consultant and a proctor at Beijing Med-Zenith Medical Technology Co; a data monitoring committee at Autus Valve Technologies; on the data safety monitoring board at Xeltis; and received research support from Xeltis and Med-Zenith Medical Technology Co. Dr Jones is an investigator, a consultant, and a proctor at Medtronic; an investigator and a consultant at Edwards; an investigator, a consultant, and a proctor at Abbott; and an investigator, a consultant, and a proctor at W. L. Gore. Dr Morray is a proctor at Medtronic and Abbott. Dr Steinberg is a proctor and a consultant at Medtronic, Gore Medical, Abbott, and B. Braun. Dr Berman is a proctor and a consultant at Abbott, B. Braun, Medtronic, and Edwards Lifesciences. The other authors report no conflicts.

Background: Safety events and technical success (TS) have been previously reported for aortic and pulmonary valvuloplasty, but a composite performance measure as a novel, patient-centered strategy has neither been developed nor been studied. This study aims to refine a procedural performance (PP) variable, a composite of TS and procedural safety, for isolated, standard-risk aortic and pulmonary valvuloplasty., Methods: A multicenter review was performed using data from the Congenital Cardiac Catheterization Project on Outcomes registry. Data were collected for all cases of isolated balloon aortic and pulmonary valvuloplasty from 2014 through 2017. Patients were excluded if they were aged <1 month, were inpatient at the time of the procedure, or had significant comorbidities, such as Williams or Noonan syndrome. Criteria for TS were developed and categorized (optimal, satisfactory, and unsatisfactory) by expert consensus based on previous outcome research. Adverse events (AE) were categorized by severity (level 1-5) using established criteria. Level 4 and 5 severity AE were considered high-severity AE. Using criteria of TS and AE severity, PP was divided into 3 composite outcome classes. Factors correlating with class III (suboptimal) PP were analyzed., Results: There were 169 cases of aortic and 270 cases of pulmonary valvuloplasty in the cohorts. In the aortic valvuloplasty cohort, a suboptimal PP (class III) occurred in 14% of cases, mostly due to high-severity AE (7%). No significant correlation between patient or case characteristics and PP was demonstrated. In the pulmonary valvuloplasty cohort, class III PP occurred in 9% of cases, predominantly due to residual valve gradient, which correlated with lower weight ( P = .02)., Conclusions: We designed a composite variable of PP consisting of TS and safety as a comprehensive measure of outcome. Incorporating both TS and AE may better reflect patient outcome than each metric measured separately. PP indices may identify areas for further investigation and quality improvement., (© 2023 The Author(s).)

Background: The Harmony transcatheter pulmonary valve (TPV) is the first U.S. Food and Drug Administration-approved device for severe pulmonary regurgitation (PR) in the native or surgically repaired right ventricular outflow tract (RVOT)., Objectives: One-year safety and effectiveness of the Harmony TPV were evaluated in patients from the Harmony Native Outflow Tract Early Feasibility Study, Harmony TPV Pivotal Study, and Continued Access Study, representing the largest cohort to date of Harmony TPV recipients., Methods: Eligible patients had severe PR by echocardiography or PR fraction ≥ 30% by cardiac magnetic resonance imaging and clinical indications for pulmonary valve replacement. The primary analysis included 87 patients who received a commercially available TPV22 (n = 42) or TPV25 (n = 45) device; 19 patients who received an early device iteration prior to its discontinuation were evaluated separately., Results: In the primary analysis, median patient age at treatment was 26 years (IQR: 18-37 years) in the TPV22 group and 29 years (IQR: 19-42 years) in the TPV25 group. At 1 year, there were no deaths; 98% of TPV22 and 91% of TPV25 patients were free from the composite of PR, stenosis, and reintervention (moderate or worse PR, mean RVOT gradient >40 mmHg, device-related RVOT reoperation, and catheter reintervention). Nonsustained ventricular tachycardia occurred in 16% of patients. Most patients had none/trace or mild PR (98% of TPV22 patients, 97% of TPV25 patients). Outcomes with the discontinued device are reported separately., Conclusions: The Harmony TPV device demonstrated favorable clinical and hemodynamic outcomes across studies and valve types through 1 year. Further follow-up will continue to assess long-term valve performance and durability., Competing Interests: Funding Support and Author Disclosures This study was supported by Medtronic. Dr Gillespie serves as a consultant for Medtronic; as an advisory board member and a consultant for Abbott; and as a consultant and principal investigator for W. L. Gore & Associates. Dr McElhinney serves as a proctor and consultant for Medtronic. Dr Jones is an investigator, a consultant, and a proctor for Medtronic; and is an investigator and a consultant for Edwards Lifesciences. Dr Levi serves as a consultant for Edwards Lifesciences and Medtronic. Dr Asnes is a consultant for Medtronic. Dr Gray receives research support as an investigator for Medtronic and Edwards Lifesciences. Dr Cabalka is an investigator and a consultant for Medtronic and Edwards Lifesciences. Dr Qureshi serves as a consultant for Medtronic and W.L. Gore & Associates. Dr Justino serves as a consultant for Abbott, Abiomed, Baylis Medtech, Chiesi USA, Edwards Lifesciences, Janssen Research and Development, Medtronic, and Pediastent; and is a cofounder of PolyVascular. Dr Benson serves as consultant for Medtronic. Mr Haugan is a full-time employee and shareholder of Medtronic. Dr Cheatham serves as a consultant, a principal investigator, a proctor, and an advisory board member for Medtronic. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Objectives: Palliative treatment of cyanotic congenital heart disease (CCHD) uses systemic-to-pulmonary conduits, often a modified Blalock-Taussig-Thomas shunt (mBTTs). Expanded polytetrafluoroethylene (ePTFE) mBTTs have associated risks for thrombosis and infection. The Human Acellular Vessel (HAV) (Humacyte, Inc) is a decellularized tissue-engineered blood vessel currently in clinical trials in adults for vascular trauma, peripheral artery disease, and end-stage renal disease requiring hemodialysis. In addition to restoring blood flow, the engineered HAV demonstrates the capacity for host cellular remodeling into native-like vasculature. Here we report preclinical evaluation of a small-diameter (3.5 mm) HAV as a mBTTs in a non-human primate model., Methods: We implanted 3.5 mm HAVs as right subclavian artery to pulmonary artery mBTTs in non-immunosuppressed juvenile rhesus macaques (n = 5). HAV patency, structure, and blood flow were assessed by postoperative imaging from 1 week to 6 months. Histology of HAVs and surrounding tissues was performed., Results: Surgical procedures were well tolerated, with satisfactory anastomoses, showing feasibility of using the 3.5 mm HAV as a mBTTs. All macaques had some immunological reactivity to the human extracellular matrix, as expected in this xenogeneic model. HAV mBTTs remained patent for up to 6 months in animals, exhibiting mild immunoreactivity. Two macaques displaying more severe immunoreactivity to the human HAV material developed midgraft dilatation without bleeding or rupture. HAV repopulation by host cells expressing smooth muscle and endothelial markers was observed in all animals., Conclusions: These findings may support use of 3.5 mm HAVs as mBTTs in CCHD and potentially other pediatric vascular indications., (© 2023 Published by Elsevier Inc. on behalf of The American Association for Thoracic Surgery.)

To evaluate short-term procedural outcomes and safety for infants < 2.5 kg who underwent catheterization with intended patent ductus arteriosus (PDA) device closure in a multi-center registry, as performance of this procedure becomes widespread. A multi-center retrospective review was performed using data from the Congenital Cardiac Catheterization Project on Outcomes (C3PO) registry. Data were collected for all intended cases of PDA closure in infants < 2.5 kg from April 2019 to December 2020 at 13 participating sites. Successful device closure was defined as device placement at the conclusion of the catheterization. Procedural outcomes and adverse events (AE) were described, and associations between patient characteristics, procedural outcomes and AEs were analyzed. During the study period, 300 cases were performed with a median weight of 1.0 kg (range 0.7-2.4). Successful device closure was achieved in 98.7% of cases with a 1.7% incidence of level 4/5 AEs, including one periprocedural mortality. Neither failed device placement nor adverse events were significantly associated with patient age, weight or institutional volume. Higher incidence of adverse events associated with patients who had non-cardiac problems (p = 0.017) and cases with multiple devices attempted (p = 0.064). Transcatheter PDA closure in small infants can be performed with excellent short-term outcomes and safety across institutions with variable case volume., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

The aim of the study was to determine the variables associated with high-quality (HQ) versus low-quality (LQ) three-dimensional rotational angiography (3DRA) and create guides for optimization of approach to 3DRA in congenital cardiac catheterization (CCC). CCC has adopted 3DRA as a mainstay, but there has not been systematic analysis of approach to and factors associated with HQ 3DRA. This was a single-center, retrospective study of 3DRAs using Canon Infinix-I platform. Reconstructions were graded by 3 interventionalists. Quality was dichotomized into HQ and LQ. Univariable analyses and multivariable logistic regression models were performed. From 8/2016 to 12/2018, 208 3DRAs were performed in 195 CCCs; median age 7 years (2, 16), weight 23 kg (12, 57). The majority of 3DRAs were performed in patients with biventricular physiology (N = 137, 66%) and in pulsatile sites (N = 144, 69%). HQ 3DRA (N = 182, 88%) was associated with greater total injection volume [2.20 mL/kg (1.44, 3.29) vs. 1.62 mL/kg (1.10, 1.98), p = 0.005] and more dilute contrast solution [60% (50, 100) vs. 100% (60, 100), p = 0.007], but not with contrast volume administered (p = 0.2) on univariable analysis. On multivariable logistic regression, HQ 3DRA was significantly associated with patient weight [OR 0.97 (95% CI (0.94, 0.99), p = 0.018], total injection volume [OR 1.04 (95% CI 1.01, 1.07) p = 0.011], and percent contrast solution [OR 0.97 (95% CI 0.95, 1.00), p = 0.022]. These data resulted in creation of scatter plots and a novel 3DRA Nomogram for estimating the probability of HQ 3DRA. This is the first study to create evidence-based contrast dose guides and nomogram for 3DRA in CCC. HQ 3DRA was associated with lower weight, higher total injection volumes, and more dilute contrast solution., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Recurrent laryngeal nerve injury leading to vocal cord paralysis is a known complication of cardiothoracic surgery. Its occurrence during interventional catheterisation procedures has been documented in case reports, but there have been no studies to determine an incidence., Objective: To establish the incidence of left recurrent laryngeal nerve injury leading to vocal cord paralysis after left pulmonary artery stenting, patent ductus arteriosus device closure and the combination of the procedures either consecutively or simultaneously., Methods: Members of the Congenital Cardiovascular Interventional Study Consortium were asked to perform a retrospective analysis to identify cases of recurrent laryngeal nerve injury after the aforementioned procedures. Twelve institutions participated in the analysis. They also contributed the total number of each procedure performed at their respective institutions for statistical purposes., Results: Of the 1337 patients who underwent left pulmonary artery stent placement, six patients (0.45%) had confirmed vocal cord paralysis. 4001 patients underwent patent ductus arteriosus device closure, and two patients (0.05%) developed left vocal cord paralysis. Patients who underwent both left pulmonary artery stent placement and patent ductus arteriosus device closure had the highest incidence of vocal cord paralysis which occurred in 4 of the 26 patients (15.4%). Overall, 92% of affected patients in our study population had resolution of symptoms., Conclusion: Recurrent laryngeal nerve injury is a rare complication of left pulmonary artery stent placement or patent ductus arteriosus device closure. However, the incidence is highest in patients undergoing both procedures either consecutively or simultaneously. Additional research is necessary to determine contributing factors that might reduce the risk of recurrent laryngeal nerve injury.

Background: The COVID-19 pandemic has posed tremendous stress on the health care system. Its effects on pediatric/congenital catheterization program practice and performance have not been described., Objectives: The purpose of this study was to evaluate how case volumes, risk-profile, and outcomes of pediatric/congenital catheterization procedures changed in response to the first wave of COVID-19 and after that wave., Methods: A multicenter retrospective observational study was performed using Congenital Cardiac Catheterization Project on Outcomes Registry (C3PO) data to study changes in volume, case mix, and outcomes (high-severity adverse events [HSAEs]) during the first wave of COVID (March 1, 2020, to May 31, 2020) in comparison to the period prior to (January 1, 2019, to February 28, 2020) and after (June 1, 2020, to December 31, 2020) the first wave. Multivariable analyses adjusting for case type, hemodynamic vulnerability, and age group were performed. Hospital responses to the first wave were captured with an electronic study instrument., Results: During the study period, 12,557 cases were performed at 14 C3PO hospitals (with 8% performed during the first wave of COVID and 32% in the postperiod). Center case volumes decreased from a median 32.1 cases/month (IQR: 20.7-49.0 cases/month) before COVID to 22 cases/month (IQR: 13-31 cases/month) during the first wave ( P  = 0.001). The proportion of cases with risk factors for HSAE increased during the first wave, specifically proportions of infants and neonates ( P  < 0.001) and subjects with renal insufficiency ( P  = 0.02), recent cardiac surgery ( P  < 0.001), and a higher hemodynamic vulnerability score ( P  = 0.02). The observed HSAE risk did not change significantly ( P  = 0.13). In multivariable analyses, odds of HSAE during the first wave of COVID (odds ratio: 0.75) appeared to be lower than that before COVID, but the difference was not significant ( P  = 0.09)., Conclusions: Despite increased case-mix complexity, C3PO programs maintained, if not improved, their performance in terms of HSAE. Exploratory analyses of practice changes may inform future harm-reduction efforts., Competing Interests: The proposed research and manuscript were reviewed by the Congenital Cardiac Catheterization Project on Outcomes (C3PO) Research and Publications Committee, but the resulting manuscript represents the views of the authors and not that of C3PO. Dr Goldstein has received consulting fees from Medtronic, W.L. Gore & Associates, Mezzion Pharmaceuticals, and PECA Labs. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (© 2022 The Authors.)

Objectives: The aim of this study was to evaluate the accuracy of cardiac magnetic resonance (CMR) in predicting coronary artery (CA) compression during transcatheter pulmonary valve implantation (TPVi)., Background: TPVi is a widely available option to treat dysfunctional right ventricle (RV)-to-pulmonary artery (PA) conduits, but CA compression is an absolute contraindication. CMR can evaluate coronary anatomy, but its utility in predicting CA compression is not well established., Methods: After Institutional Review Board approval was obtained, all patients at 9 centers with attempted TPVi in RV-PA conduits and recent CMR (≤12 months) were analyzed. A core laboratory reviewed all CMR studies for the shortest orthogonal distance from a CA to the conduit, the shortest distance from a CA to the most stenotic area of the conduit, and subjective assessment of CA compression risk., Results: Among 231 patients, TPVi was successful in 198 (86%); in 24 (10%), balloon testing precluded implantation (documented CA compression or high risk). Distance to the RV-PA conduit ≤2.1 mm (area under the curve [AUC]: 0.70) and distance to most stenotic area ≤13.1 mm (AUC: 0.69) predicted CA compression. Subjective assessment had the highest AUC (0.78), with 96% negative predictive value. Both distances and qualitative assessment remained independently associated with CA compression when controlling for abnormal coronary anatomy or degree of conduit calcification., Conclusions: CMR can help predict the risk for CA compression during TPVi in RV-PA conduits but cannot completely exclude CA compression. CMR may assist in patient selection and counseling families prior to TPVi, although balloon testing remains essential., Competing Interests: Funding Support and Author Disclosures This research was supported by funding from the Percy J. Murphy and Mary C. Murphy Endowed Children’s Research Fund. This grant does not have any relationship with industry. The authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2022 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

The objective of this study was to evaluate the impact of the regular introduction of new technologies into interventional cardiac catheterization procedures, in this case new atrial septal defect (ASD) closure devices, while conducting a multi-center collaborative initiative to reduce radiation usage during all procedures. Data were collected prospectively by 8 C3PO institutions between January 1, 2014 and December 31, 2017 for ASD device closure procedures in the cardiac catheterization lab during a quality improvement (QI) initiative aimed at reducing patient radiation exposure. Radiation exposure was measured in dose area product per body weight (µGy*m 2 /kg). Use of proposed practice change strategies at the beginning and end of the QI intervention period was assessed. Radiation exposure was summarized by institution and by initial type of device used for closure. This study included 602 ASD device closures. Without changes in patient characteristics, total fluoroscopy duration, or number of digital acquisitions, median radiation exposure decreased from 37 DAP/kg to 14 DAP/kg from 2014 to 2017. While all individual centers decreased overall median DAP/kg, the use of novel devices for ASD closure correlated with a temporary period of worsening institutional radiation exposure and increased fluoroscopy time. The introduction of new ASD closure devices resulted in increased radiation exposure during a QI project designed to reduce radiation exposure. Therefore, outcome assessment must be contextualized in QI projects, hospital evaluation, and public reporting, to acknowledge the expected variation during innovation and introduction of novel therapies., (© 2021. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Tissue-engineered vascular grafts (TEVGs) have the potential to advance the surgical management of infants and children requiring congenital heart surgery by creating functional vascular conduits with growth capacity., Methods: Herein, we used an integrative computational-experimental approach to elucidate the natural history of neovessel formation in a large animal preclinical model; combining an in vitro accelerated degradation study with mechanical testing, large animal implantation studies with in vivo imaging and histology, and data-informed computational growth and remodeling models., Results: Our findings demonstrate that the structural integrity of the polymeric scaffold is lost over the first 26 weeks in vivo, while polymeric fragments persist for up to 52 weeks. Our models predict that early neotissue accumulation is driven primarily by inflammatory processes in response to the implanted polymeric scaffold, but that turnover becomes progressively mechano-mediated as the scaffold degrades. Using a lamb model, we confirm that early neotissue formation results primarily from the foreign body reaction induced by the scaffold, resulting in an early period of dynamic remodeling characterized by transient TEVG narrowing. As the scaffold degrades, mechano-mediated neotissue remodeling becomes dominant around 26 weeks. After the scaffold degrades completely, the resulting neovessel undergoes growth and remodeling that mimicks native vessel behavior, including biological growth capacity, further supported by fluid-structure interaction simulations providing detailed hemodynamic and wall stress information., Conclusions: These findings provide insights into TEVG remodeling, and have important implications for clinical use and future development of TEVGs for children with congenital heart disease., Competing Interests: Competing interestsGunze Limited, the manufacturer of the scaffold, provided further support for this project to C.K.B. The remaining authors declare no competing interests., (© The Author(s) 2022.)

Background: Three-dimensional printing is increasingly utilised for congenital heart defect procedural planning. CT or MR datasets are typically used for printing, but similar datasets can be obtained from three-dimensional rotational angiography. We sought to assess the feasibility and accuracy of printing three-dimensional models of CHD from rotational angiography datasets., Methods: Retrospective review of CHD catheterisations using rotational angiography was performed, and patient and procedural details were collected. Imaging data from rotational angiography were segmented, cleaned, and printed with polylactic acid on a Dremel® 3D Idea Builder (Dremel, Mount Prospect, IL, USA). Printing time and materials' costs were captured. CT scans of printed models were compared objectively to the original virtual models. Two independent, non-interventional paediatric cardiologists provided subjective ratings of the quality and accuracy of the printed models., Results: Rotational angiography data from 15 catheterisations on vascular structures were printed. Median print time was 3.83 hours, and material costs were $2.84. The CT scans of the printed models highly matched with the original digital models (root mean square for Hausdorff distance 0.013 ± 0.003 mesh units). Independent reviewers correctly described 80 and 87% of the models (p = 0.334) and reported high quality and accuracy (5 versus 5, p = NS; κ = 0.615)., Conclusion: Imaging data from rotational angiography can be converted into accurate three-dimensional-printed models of CHD. The cost of printing the models was negligible, but the print time was prohibitive for real-time use. As the speed of three-dimensional printing technology increases, novel future applications may allow for printing patient-specific devices based on rotational angiography datasets.

Primary pulmonary vein stenosis (PPVS) is an emerging problem among infants. In contrast to acquired disease, PPVS is the development of stenosis in the absence of preceding intervention. While optimal care approaches remain poorly characterized, over the past decade, understanding of potential pathophysiological mechanisms and development of novel therapeutic strategies are increasing. A multidisciplinary team of health care providers was assembled to review the available evidence and provide a common framework for the diagnosis, management, and treatment of PPVS during infancy. To address knowledge gaps, institutional and multi-institutional approaches must be employed to generate knowledge specific to ex-premature infants with PPVS. Within individual institutions, creation of a team comprised of dedicated health care providers from diverse backgrounds is critical to accelerate clinical learning and provide care for infants with PPVS. Multi-institutional collaborations, such as the PVS Network, provide the infrastructure and statistical power to advance knowledge for this rare disease., (© 2021. The Author(s), under exclusive licence to Springer Nature America, Inc. part of Springer Nature.)

Bioabsorbable materials made from polymeric compounds have been used in many fields of regenerative medicine to promote tissue regeneration. These materials replace autologous tissue and, due to their growth potential, make excellent substitutes for cardiovascular applications in the treatment of congenital heart disease. However, there remains a sizable gap between their theoretical advantages and actual clinical application within pediatric cardiovascular surgery. This review will focus on four areas of regenerative medicine in which bioabsorbable materials have the potential to alleviate the burden where current treatment options have been unable to within the field of pediatric cardiovascular surgery. These four areas include tissue-engineered pulmonary valves, tissue-engineered patches, regenerative medicine options for treatment of pulmonary vein stenosis and tissue-engineered vascular grafts. We will discuss the research and development of biocompatible materials reported to date, the evaluation of materials in vitro, and the results of studies that have progressed to clinical trials.

Background: Stent implantation (SI) is more effective than balloon angioplasty for the treatment of coarctation of the aorta (CoA). Due to technical factors, balloon angioplasty is more commonly performed in small patients. We sought to evaluate outcomes of percutaneous adult sized SI for the treatment of CoA in small patients., Methods: A single-center retrospective review of all patients ≤20 kg who underwent percutaneous adult sized SI for native or recurrent CoA from 2004 to 2015 was performed., Results: Thirty-nine patients (20 patients ≤10 kg) were identified, with 28 (71.8%) having recurrent CoA and 22 (56.4%) previously failed balloon angioplasty. At the time of SI, the median (range) patient age and weight were 1.1 (0.3-7.9) years and 10 (5.5-20.4) kg, respectively. SI resulted in significant improvements in the median gradient (26 mm Hg [interquartile range (IQR), 18-42] to 0 mm Hg [IQR, 0-2]; P < 0.05) and median minimum diameter (3.6 mm [IQR, 2.4-4.8] to 7.7 mm [IQR, 6.5-9.4]; P <0.05). Seven patients (18%) had procedural adverse events. Twenty-seven (69%) patients underwent elective reintervention at a median time of 49.3 (IQR, 26.5-63.2) months from SI, with 8 (21%) stents requiring repeat SI for stent fracture. Over a median follow-up of 67.2 (IQR, 33.8-116.1) months, 25 patients (69%) were without hypertension or blood pressure gradient. Three (11%) patients developed femoral arterial occlusion., Conclusions: Adult sized SI is an alternative to surgical intervention for small patients with CoA. SI carries a risk of access-related complications, which may improve with the development of lower profile stents with adult sized maximum diameters.

Objectives: We aimed to evaluate the utility of computed tomography angiography (CTA) for coronary compression (CC) prediction in patients with congenital heart disease undergoing balloon-expandable transcatheter pulmonary valve replacement (TPVR)., Background: Coronary compression is a serious complication of TPVR, but the value of preprocedural CTAs to assess CC risk is largely unexplored., Methods: In all, 586 patients underwent TPVR between January 2009 and July 2018. Adults with a pre-TPVR CTA and children with a CTA performed less than one year prior to TPVR were included. Patients with poor CTA image quality or with aborted cases due to reasons other than CC were excluded. Sixty-six patients were finally included. Cardiac anatomy was assessed via multiplanar reconstruction of CTAs., Results: Coronary compression occurred in 9 (14%) of the 66 patients who underwent TPVR. Most CC cases (seven of nine) occurred in patients with conduits. Proximity of the right ventricular outflow tract (RVOT) landing zone to the coronary arteries and to the chest wall was a significant risk factor for compression ( P < .001 and P = .019, respectively). Compression risk increased significantly if patients had an RVOT to coronary artery distance of ≤3 mm ( P < .001) and an RVOT to chest wall distance of ≤8 mm ( P = .026). Anomalous course of coronary arteries was another significant univariate risk factor ( P = .003)., Conclusions: Right ventricular outflow tract landing zone distance of ≤3 mm to a coronary artery, landing zone distance of ≤8 mm to the chest wall, and anomalous coronary arteries are associated with increased CC risk. Electrocardiogram gating may not be necessary if coronary arteries are opacified on CTAs. Larger studies are needed to explore and confirm these coronary artery compression risk factors.

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., (Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)

Background: Transcatheter pulmonary valve replacement (TPVR) is associated with a risk of procedural serious adverse events (SAE) and exposure to ionizing radiation., Objectives: The purpose of this study was to define the risk of, and associations with, SAE and high-dose radiation exposure using large-scale registry data., Methods: The analysis of the multicenter C3PO-QI registry was limited to patients who underwent TPVR from January 1, 2014, to December 31, 2016. SAE were defined as the occurrence of ≥1 moderate, major, or catastrophic events. Radiation dose was reported as dose area product adjusted for weight. Associations with outcome measures were explored in univariate and multivariable analyses., Results: A total of 530 patients (59% male) underwent TPVR at a median age of 18.3 years (interquartile range [IQR]: 12.9 to 27.3 years) and weight of 58 kg (IQR: 43 to 77 kg) at 14 centers. Implant substrate included homograft (41%), bioprosthesis (30%), native right ventricular outflow tract (RVOT) (27%) and other (2%). TPVR indications were pulmonary insufficiency (28%), stenosis (23%), and mixed (49%). AE and SAE occurred in 26% and 13% of cases, respectively, including 1 mortality. SAE were more frequent in homograft conduit than other RVOT substrates, although SAE type and severity differed between implant substrates. Median radiation dose was 198 μGy·m 2 /kg (IQR: 94 to 350 μGy·m 2 /kg). Higher radiation dose was associated with older age, greater RVOT obstruction, and concomitant interventions (p < 0.001). During a median follow-up duration of 1 year, 13.3% underwent catheterization, surgery, or both, unrelated to infection. Younger age, smaller size, and hemodynamic and anatomic factors indicative of greater RVOT obstruction were associated with TPV reintervention., Conclusions: The incidence of SAE during TPVR in the C3PO-QI registry is high, but mortality is uncommon. Radiation dose is greater than for other congenital interventions and is associated with patient and procedural factors. Reintervention is common during early follow-up., (Copyright © 2020 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objective: We describe the technical considerations of transcatheter implantation of the CardioMEMS™ HF System (Abbott, Abbott Park, IL) in adult patients with complex palliated congenital heart disease (CHD) and advanced heart failure (HF)., Background: Ambulatory pulmonary artery (PA) pressure monitoring with implantable hemodynamic monitors (IHMs) has been shown to reduce HF-related hospital admissions in non-CHD populations. HF is a common late cardiovascular complication in adult CHD necessitating better understanding of IHM application in this population., Methods: We analyzed adults with complex CHD and advanced HF who were referred for CardioMEMS™ device implantation (2015-2018). Feasibility of device implantation, defined by successful device implantation and calibration, and procedural outcomes were evaluated., Results: CardioMEMS™ was successfully implanted in all 14 adults (35.5 ± 9.2 years old, 72 ± 12 kg) with complex CHD (single ventricle/Fontan, n = 8 [57%]; d-transposition of the great arteries/atrial switch, n = 6 [43%]). The device was delivered via femoral venous access in 13 (93%) patients and implanted in the left PA in 12 (86%). A long sheath was used in 8 (57%) patients, including 5/6 with an atrial switch operation. There was one device migration that did not require retrieval., Conclusions: Transcatheter implantation of an IHM is feasible in select complex adult CHD patients with advanced HF. Further studies evaluating integration of ambulatory hemodynamics and the impact on clinical care are needed. This technology has the potential to improve medical management of advanced HF in patients with Fontan and atrial switch physiologies and provide new insights into their ambulatory hemodynamics., (© 2019 Wiley Periodicals, Inc.)

Objectives: To describe longer term outcomes for infants <6 kg undergoing percutaneous occlusion of the patent ductus arteriosus (PDA)., Study Design: This was a retrospective cohort study of infants <6 kg who underwent isolated percutaneous closure of the PDA at a single, tertiary center (2003-2017). Cardiopulmonary outcomes and device-related complications (eg, left pulmonary artery obstruction) were examined for differences across weight thresholds (very low weight, <3 kg; low weight, 3-<6 kg). We assessed composite measures of respiratory status during and beyond the initial hospitalization using linear mixed effects models., Results: In this cohort of lower weight infants, 92 of 106 percutaneous occlusion procedures were successful. Median age and weight at procedure were 3.0 months (range, 0.5-11.1 months) and 3.7 kg (range, 1.4-5.9 kg), respectively. Among infants with pulmonary artery obstruction on initial postprocedural echocardiograms (n = 20 [22%]), obstruction persisted through hospital discharge in 3 infants. No measured variables were associated with device-related complications. Rates of oxygenation failure (28% vs 8%; P < .01) and decreased left ventricular systolic function (29% vs 5%; P < .01) were higher among very low weight than low weight infants. Pulmonary scores decreased (indicating improved respiratory status) following percutaneous PDA closure., Conclusions: Percutaneous PDA occlusion among lower weight infants is associated with potential longer term improvements in respiratory health. Risks of device-related complications and adverse cardiopulmonary outcomes, particularly among very low weight infants, underscore the need for continued device modification. Before widespread use, clinical trials comparing percutaneous occlusion vs alternative treatments are needed., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Objective: We sought to describe the leaflet morphology variation in the Melody Transcatheter Pulmonary Valve (TPV) and evaluate associated outcomes. The Melody TPV is constructed from harvested bovine jugular venous valves which have been rigorously tested. Natural anatomic leaflet variations are seen in the Melody TPV but have not been evaluated., Design: A Melody TPV leaflet morphology classification system was devised after reviewing a subset of photographed and implanted TPVs. All images were blindly reviewed by implanters and classified. Midterm hemodynamic outcomes and complications of the Melody TPVs were compared by leaflet morphology., Results: Photographed Melody TPVs implanted between 2011 and 2016 (n = 62) were categorized into the following leaflet morphology types: A-symmetric trileaflet (47%); B-asymmetric trileaflet with a single small leaflet (32%); C-asymmetric trileaflet with a single large leaflet (16%); D-rudimentary leaflet with near bicuspid appearance (5%). Acceptable hemodynamic function at 6 months postimplantation was seen in 97.5% of valves. Over a median follow-up of 1.5 years (range 0-4.4 years), two TPVs (Type A) had > mild regurgitation. Nine TPVs developed complications (endocarditis, 3; stent fracture, 2; refractory arrhythmia, 1; conduit replacement, 2; death, 1), of which 6 required reintervention. There was no significant difference in outcomes based on Melody TPV leaflet morphology type., Conclusions: The Melody TPV can be classified into one of four categories based on leaflet morphology. Study outcomes were not associated with leaflet morphology. Further documentation and evaluation of Melody TPV morphology may lead to better understanding of this technology., (© 2018 Wiley Periodicals, Inc.)

Objective: We sought to identify a time during cardiac ejection when the instantaneous pressure gradient (IPG) correlated best, and near unity, with peak-to-peak systolic ejection gradient (PPSG) in patients with congenital aortic stenosis. Noninvasive echocardiographic measurement of IPG has limited correlation with cardiac catheterization measured PPSG across the spectrum of disease severity of congenital aortic stenosis. A major contributor is the observation that these measures are inherently different with a variable relationship dependent on the degree of stenosis., Design: Hemodynamic data from cardiac catheterizations utilizing simultaneous pressure measurements from the left ventricle (LV) and ascending aorta (AAo) in patients with congenital valvar aortic stenosis was retrospectively reviewed over the past 5 years. The cardiac cycle was standardized for all patients using the percentage of total LV ejection time (ET). Instantaneous gradient at 5% intervals of ET were compared to PPSG using linear regression and Bland-Altman analysis., Results: A total of 22 patients underwent catheterization at a median age of 13.7 years (interquartile range [IQR] 10.3-18.0) and median weight of 51.1 kg (IQR 34.2-71.6). The PPSG was 46.5 ± 12.6 mm Hg (mean ± SD) and correlated suboptimally with the maximum and mean IPG. The midsystolic IPG (occurring at 50% of ET) had the strongest correlation with the PPSG ( PPSG = 0.97(IPG50%)-1.12, R 2  = 0.88), while the IPG at 55% of ET was closest to unity ( PPSG = 0.997(IPG55%)-1.17, R 2  = 0.87)., Conclusions: The commonly measured maximum and mean IPG are suboptimal estimates of the PPSG in congenital aortic stenosis. Using catheter-based data, IPG at 50%-55% of ejection correlates well with PPSG. This may allow for a more accurate estimation of PPSG via noninvasive assessment of IPG., (© 2017 Wiley Periodicals, Inc.)

Objectives: The authors sought to identify risk factors associated with major adverse events (MAEs) in infants <6 kg undergoing transcatheter patent ductus arteriosus (PDA) occlusion., Background: Transcatheter PDA occlusion is among the safest of interventional cardiac procedures in adults and older children, but use among infants <6 kg has not been characterized adequately., Methods: Using the IMPACT (IMproving Pediatric and Adult Congenital Treatments) registry, we identified infants <6 kg undergoing transcatheter PDA occlusion (January 1, 2011, to March 1, 2015). Using mixed-effects multivariate regression, the authors assessed characteristics predictive of MAE or composite failure (procedural failure or MAE). Individual safety metrics (e.g., embolization, malposition) were also examined for differences across weight thresholds: extremely low weight (LW) (<2 kg), very LW (2 to <4 kg), and LW (4 to <6 kg)., Results: Transcatheter PDA occlusion was attempted in 747 infants <6 kg at 73 hospitals. Rate of procedural success was 94.3%. MAEs were observed in 12.6% of cases; the most common events were acute arterial injury and device embolization in 3.5% and 2.4% of cases, respectively. Younger age (<30 days) was associated with greater risk of a MAE (risk ratio: 3.3; 95% confidence interval: 1.5 to 7.6) and composite failure (risk ratio: 3.0; 95% confidence interval: 1.4 to 6.7). Risk of embolization was higher among extremely LW (10.5%) than very LW or LW infants (1.6% and 2.5%, respectively; p = 0.050)., Conclusions: Among infants <6 kg, transcatheter PDA occlusion is technically feasible, but risks of MAE are noteworthy. These findings may help inform patient selection and procedural approach for transcatheter PDA occlusion and direct targeted research efforts to support the practice of evidence-based medicine., (Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: The aim of this study was to evaluate practice patterns and outcomes of a contemporary group of patients undergoing balloon aortic valvuloplasty (BAV) for congenital aortic stenosis (AS)., Background: BAV is the most common treatment for isolated congenital AS., Methods: Within the IMPACT (Improving Pediatric and Adult Congenital Treatments) Registry, all BAV procedures performed between January 2011 and March 2015 were identified. Procedures were separated into those performed for critical versus noncritical AS. Outcomes were stratified into optimal, adequate, and inadequate, with optimal and adequate outcomes defining "successful" procedures. Multivariate logistic regression was used to identify patient and procedural characteristics associated with unsuccessful BAV. Mortality and adverse events rates were compared across patient cohorts., Results: Of the 1,026 isolated BAV procedures captured in IMPACT, 718 (70%) were "successful." Success rates were 70.9% for noncritical AS (n = 916) and 62.7% for critical AS (n = 110). Multivariate analysis revealed that prior cardiac catheterization, mixed valve disease, baseline aortic valve gradient >60 mm Hg, baseline aortic insufficiency greater than mild, presence of a trainee, and multiple balloon inflations were associated with unsuccessful BAV in the noncritical AS cohort. There were no factors associated with unsuccessful procedures in the critical AS group. No procedural deaths occurred, but 2.4% of patients did not survive to hospital discharge. Adverse events occurred in 15.8% of all cases and were more frequent in procedures performed for critical AS (30.0% vs. 14.1%; p < 0.001)., Conclusions: BAV is an effective treatment for congenital AS with low rates of mortality and adverse events. Patients with critical AS have a higher risk for procedure-related adverse events., (Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Context: Patent ductus arteriosus (PDA) is a precursor to morbidity and mortality. Percutaneous (catheter-based) closure is the procedure of choice for adults and older children with a PDA, but use during infancy (<1 year) is not well characterized., Objective: Investigate the technical success and safety of percutaneous PDA closure during infancy., Data Sources: Scopus, Web of Science, Embase, PubMed, and Ovid (Medline) were searched through December 2015 with no language restrictions., Study Selection: Publications needed to clearly define the intervention as percutaneous PDA closure during infancy (<1 year of age at intervention) and must have reported adverse events (AEs)., Data Extraction: The study was performed according to the Systematic Reviews and Meta-Analysis checklist and registered prospectively. The quality of the selected studies was critically examined. Data extraction and assignment of AE attributability and severity were independently performed by multiple observers. Outcomes were agreed on a priori. Data were pooled by using a random-effects model., Results: Thirty-eight studies were included; no randomized controlled trials were found. Technical success of percutaneous PDA closure was 92.2% (95% confidence interval [CI] 88.8-95.0). Overall AE and clinically significant AE incidence was 23.3% (95% CI 16.5-30.8) and 10.1% (95% CI 7.8-12.5), respectively. Significant heterogeneity and publication bias were observed., Limitations: Limitations include lack of comparative studies, lack of standardized AE reporting strategy, and significant heterogeneity in reporting., Conclusions: Percutaneous PDA closure during infancy is feasible and associated with few catastrophic AEs; however, the limitations constrain the interpretability and generalizability of the current findings., (Copyright © 2017 by the American Academy of Pediatrics.)

We sought to describe the use and outcomes of small, medium and large premounted stents in patients with congenital heart disease, including incidence of and risk factors for re-intervention and development of in-stent stenosis. Premounted stents offer several advantages over traditional manually crimped bare-metal stents, especially in small patients. There are no data describing the medium-term effectiveness and outcomes of premounted stents in congenital heart disease. We performed a single-center retrospective review of all small, medium and large premounted stents implanted over an 8-year period. Premounted stents were implanted in 71 vessels within 59 patients with a 97 % success rate. Regardless of implantation site, premounted stent implantation resulted in significant improvements in vessel size and pressure gradient (p < 0.0001). Over a median follow-up duration of 3.1 years [interquartile range (IQR) 1.3-5.2], 25 patients (43 %) required re-intervention (18 catheter based, 3 surgical and 4 hybrid) at a median time of 1.4 years (IQR 0.9-3.0) from implant. Factors associated with re-intervention included age ≤1.9 years [hazard ratio (HR) 2.4, p = 0.03], weight ≤11.5 kg (HR 2.5, p = 0.03) and bare-metal premounted stents compared to covered premounted stents (HR 4.2, p = 0.001). In-stent stenosis was diagnosed in 42 % of premounted stents which underwent follow-up angiography. No identified characteristics were associated with in-stent stenosis, including "oversizing" the premounted stent. Small, medium and large premounted stents are effective in treating vascular stenosis in congenital heart disease. Frequent follow-up is required, especially in smaller patients with expected somatic growth, and to evaluate for in-stent stenosis which occurs in nearly half of premounted stents.

Transcatheter pulmonary valves are being used off-label to treat pulmonary insufficiency in patched right ventricular outflow tracts (RVOTs). We describe the first reported cases of patched RVOT rupture, during balloon sizing for percutaneous pulmonary valve implantation, in two patients with tetralogy of Fallot status post repair. Both RVOTs were too large for subsequent catheter-based intervention. The ruptures remained stable over time, and both patients were managed conservatively with follow-up imaging., (© 2015 Wiley Periodicals, Inc.)

Objectives: Patients with congenital heart disease may have limited venous access routes as a result of multiple central venous catheters, surgical interventions, and catheterization procedures. Unconventional venous access includes transhepatic central venous catheter. We evaluated transhepatic central venous catheter placed in patients with congenital heart disease and risk factors associated with complications and outcomes., Design: Demographic, procedural, and complication data were retrospectively collected on all patients who underwent transhepatic central venous catheter placement at our center over the past 10 years., Setting: This study was completed in a tertiary congenital heart center., Patients: A total of 92 transhepatic central venous catheters were placed in 54 patients (63% male patients). The median age and weight of the patient population was 5.7 months and 5.5 kg, respectively., Interventions: Placement of a transhepatic central venous catheter., Measurements and Main Results: Successful catheter placement occurred in 96% of cases with median procedure time of 54 minutes with a procedural complication rate of 14%. A total of 86 complications occurred in 54 catheters placed during 2,166 catheter-days (39.7 complications per 1,000 catheter-days). Individual complication rates per 1,000 catheter-days included catheter dysfunction (14.8), dislodgement (8.8), systemic infection (5.1), thrombosis (4.2), local infection (3.7), and bleeding (3.2). Two complications contributed to patient deaths. Factors associated with developing complications included polyurethane central venous catheters (p = 0.03) and catheter duration at least 21 days (p = 0.004). The overall mortality in this population was 50% with median length of hospitalization of 49 days (interquartile range, 33-97)., Conclusions: Transhepatic central venous catheters represent a viable option for patients with limited access. Polyurethane catheters and catheter duration at least 21 days are associated with increased transhepatic central venous catheter complications. Although complication rates are higher than more traditional forms of central venous catheters, the long duration of hospitalization and high mortality rates in this patient population attest to their risks for poor outcomes irrespective of venous access.

Background: Few data exist regarding outcomes after resection versus embolic treatment of symptomatic metastatic carcinoid and neuroendocrine tumors. The purpose of this study was to determine whether cytoreduction provides any benefit over embolic management of diffuse neuroendocrine tumors., Methods: A prospective database of 734 patients treated at our institution was retrospectively queried for symptomatic metastatic tumors treated with embolization or cytoreduction. Patients were compared with regard to pretreatment performance status, relief of symptoms, and survival., Results: A total of 120 patients were identified: 59 undergoing embolization and 61 undergoing cytoreduction. Twenty-three patients had palliative cytoreduction (gross residual disease). Pretreatment performance status (Eastern Cooperative Oncology Group) was similar for both groups: .7+/-.70 (embolization) versus .8+/-.72 (cytoreduction; P=.27). Complete symptomatic relief was observed in 59% and partial relief in 32% of patients who underwent embolization, with a mean symptom-free interval of 22+/-13.6 months. A total of 69% of patients who underwent cytoreduction had complete symptomatic relief, and 23% had partial relief (P=.08 vs. embolization). The mean duration of relief was 35+/-22.0 months (P<.001 vs. embolization). The mean survival for the patients who underwent embolization was 24+/-15.8 months versus 43+/-26.1 months for those who underwent cytoreduction (P<.001). Survival in patients who underwent palliative cytoreduction was 32+/-18.9 months (P<.001 vs. embolization), whereas it was 50+/-27.6 months in patients who underwent curative resection (P<.001 vs. embolization; P<.001 vs. palliative)., Conclusions: Cytoreduction for metastatic neuroendocrine tumors resulted in improved symptomatic relief and survival when compared with embolic therapy in this nonrandomized study. Cytoreduction should be pursued whenever possible even if complete resection may not be achievable.

Background: The purpose of this study was to determine risk factors for development of malignant ascites and its prognostic significance in patients with pancreatic cancer., Methods: A prospective database was queried to identify patients with pancreatic cancer who develop ascites. Stage at presentation, size, and location of primary tumor, treatment received and length of survival after onset of ascites were determined., Results: A total of 15 patients were identified. Of which 4 patients (1 stage II, 3 stage III) underwent pancreaticoduodenectomy and manifested with ascites 2, 3, 24 and 47 months after surgery (tumor size 2.9 +/- 1.32 cm). All but one of the remaining 11 patients (tumor size 4.4 +/- 3.38 cm) presented with metastatic disease, and all developed malignant ascites 9 months after diagnosis, dying 2 months later. Resected patients lived longer before the onset of ascites, but not after., Conclusion: Once diagnosed, ascites in pancreatic cancer patients heralds imminent death. Limited survival should be considered when determining the aggressiveness of further intervention.