Sharon L. Cheatham

Use and Performance of the Melody Transcatheter Pulmonary Valve in Native and Postsurgical, Nonconduit Right Ventricular Outflow Tracts

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.

The medtronic melody® transcatheter pulmonary valve implanted at 24-mm diameter—it works

We report the Melody valve implanted and/or expanded to 24‐mm diameter.

Percutaneous Patent Ductus Arteriosus (PDA) Closure in Very Preterm Infants: Feasibility and Complications

Background Percutaneous 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 Results Retrospective 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). Conclusions Among 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.

Patient Selection Process for the Harmony Transcatheter Pulmonary Valve Early Feasibility Study

This early feasibility study was designed to obtain in vivo data to confirm assumptions on device loading conditions of the Medtronic Harmony transcatheter pulmonary valve (TPV). Secondary objectives included procedural feasibility, safety, and valve performance. The Harmony TPV was developed for nonsurgical pulmonary valve replacement in non-right ventricle-pulmonary artery conduit patients. The Native Outflow Tract TPV Research Clinical Study was the first study approved under the Food and Drug Administration Early Feasibility Study guidance. Enrollment required that patient anatomy be precisely matched to the single-size Harmony TPV implant, necessitating a rigorous selection process. The study was nonrandomized, prospective, and performed at 3 sites. All patients met standard indications for surgical pulmonary valve replacement. The goal of the screening committee was to match the candidate anatomy to predetermined engineering criteria thought to be predictive of secure Harmony TPV implantation for the single-size device under study. A majority of the screening committee was required to recommend a patient as eligible for implant. A total of 270 patients underwent prescreening cardiac magnetic resonance imaging, 66 were enrolled and received a computed tomography scan (24%), 21 met criteria for implant and were catheterized (8%), and 20 underwent implant. Nineteen of 20 met criteria for implant success. In conclusion, the Medtronic Harmony TPV represents an emerging therapeutic option for patients with complex postoperative right ventricular outflow tract failure. The initial clinical evaluation of this technology was unique, and the highly variable anatomy of this population required careful screening to ensure acceptable device fit.

An Overview of Pulmonary Atresia and Major Aortopulmonary Collateral Arteries

Pulmonary atresia with ventricular septal defect and major aortopulmonary collateral arteries (PA/VSD/MAPCAs) is a rare and complex congenital cardiac lesion that has historically carried a poor prognosis. With advancements in surgical management, we have seen an improvement in the outcomes for children affected by this disease. However, this population continues to present challenges due to the complex anatomy and physiology associated with PA/VSD/MAPCA. This summary of material presented during one of the nursing sessions of the 2014 Meeting of the Pediatric Cardiac Intensive Care Society provides an overview for those in cardiac intensive care units who do not have a large experience with this lesion. We will review the anatomy, physiology, surgical approach, postoperative management strategies, and cardiac catheter intervention options for PA/VSD/MAPCAs. We will also discuss recent innovations that may lead to continued improvement in outcomes for this challenging patient population.

Iatrogenic embolization and transcatheter retrieval of a ventricular septal defect occluder in a dog

A 7-month-old Irish Setter underwent transcatheter therapy of a muscular ventricular septal defect (VSD) and pulmonary valve stenosis. Standard devices for muscular VSD closure could not span the interventricular septum due to right ventricular hypertrophy, and an Amplatzer post-infarction muscular VSD occluder with a wider waist was successfully implanted. Following VSD closure, inflation of the balloon dilation catheter during balloon pulmonary valvuloplasty resulted in iatrogenic embolization of the VSD occluder to the left ventricular outflow tract. Retrieval and reimplantation of the device was achieved using a snare catheter. This report describes a potential complication and management during intracardiac device implantation in a dog. Additionally, the case illustrates that the Amplatzer post-infarction muscular VSD occluder holds potential value in animals with a hypertrophied interventricular septum that cannot be spanned using a conventional device.

Stenting of the right ventricular outflow tract in 2 dogs for palliation of dysplastic pulmonary valve stenosis and right-to-left intracardiac shunting defects.

Two dogs with severe dysplastic pulmonary valve stenosis and right-to-left shunting defects (patent foramen ovale, perimembranous ventricular septal defect) underwent palliative stenting of the right ventricular outflow tract and pulmonary valve annulus using balloon expandable stents. One dog received 2 over-lapping bare metal stents placed 7 months apart; the other received a single covered stent. Both procedures were considered technically successful with a reduction in the transpulmonary valve pressure gradient from 202 to 90 mmHg in 1 dog and from 168 to 95 mmHg in the other. Clinical signs of exercise intolerance and syncope were temporarily resolved in both dogs. However, progressive right ventricular concentric hypertrophy, recurrent stenosis, and erythrocytosis were observed over the subsequent 6 months leading to poor long-term outcomes. Stenting of the right ventricular outflow tract is feasible in dogs with severe dysplastic pulmonary valve stenosis, though further study and optimization of the procedure is required.

Intravascular Ultrasound Characterization of a Tissue-Engineered Vascular Graft in an Ovine Model.

Patients who undergo implantation of a tissue-engineered vascular graft (TEVG) for congenital cardiac anomalies are monitored with echocardiography, followed by magnetic resonance imaging or angiography when indicated. While these methods provide data regarding the lumen, minimal information regarding neotissue formation is obtained. Intravascular ultrasound (IVUS) has previously been used in a variety of conditions to evaluate the vessel wall. The purpose of this study was to evaluate the utility of IVUS for evaluation of TEVGs in our ovine model. Eight sheep underwent implantation of TEVGs either unseeded or seeded with bone marrow-derived mononuclear cells. Angiography, IVUS, and histology were directly compared. Endothelium, tunica media, and graft were identifiable on IVUS and histology at multiple time points. There was strong agreement between IVUS and angiography for evaluation of luminal diameter. IVUS offers a valuable tool to evaluate the changes within TEVGs, and clinical translation of this application is warranted.

Mustard baffle obstruction and leak – How successful are percutaneous interventions in adults?

Atrial switch operations for D-Transposition of the great arteries (D-TGA) were performed until the late 20th century. These patients have substantial rates of re-operation, particularly for baffle related complications. This study sought to analyze the efficacy of percutaneous transcatheter intervention (PTI) for baffle leak and/or stenosis in adult atrial switch patients. Adult patients with a prior atrial switch operation who underwent heart catheterization (2002-2014) at a tertiary adult congenital heart disease referral center were retrospectively analyzed. In 58 adults (30 ± 8 years, 75% men, 14% New York Heart Association (NYHA) functional class ≥2) who underwent 79 catheterizations, PTI was attempted in 50 (baffle leak (n = 10, 20%), stenosis (n = 27, 54%), or both (n = 13, 26%)). PTI was successful in 45 and 5 were referred for surgery due to complex anatomy. A total of 40 bare metal stents, 18 covered stents, 16 occlusion devices, 2 angioplasties, and 1 endovascular graft were deployed. In isolated stenosis, there was improvement in NYHA functional class after PTI (8 vs. 0 patients were NYHA FC > 2, p = 0.004), which was matched by improvement in maximal oxygen consumption on exercise testing (VO2) (25.1 ± 5.4 mL/kg/min vs. 27.9 ± 9 mL/kg/min, p = 0.03). There were no procedure-related deaths or emergent surgeries in this cohort. This single-center cohort is the largest reported series of adult atrial switch operation patients who have undergone PTI for baffle stenosis and/or leak. We demonstrate that PTI with an expert multi-disciplinary team is a safe and effective alternative to surgery in adult patients with an atrial switch operation.

Parents’ Perspective on the Hybrid Approach

The diagnosis of HLHS can be devastating for parents, whether diagnosed prenatally or after birth. The parents’ perspective on the hybrid approach to managing infants with HLHS, and the psychosocial impact, have not been well reported. Parents need and expect honesty, empathy, and compassion during delivery of the diagnosis and therapeutic options. The information needs to be presented in layman’s terms, avoiding too much clinical jargon and utilizing pictures to help provide a clear understanding of the severity of the disease and surgical options. During the interstage period, parents are faced with other stressors before undergoing Comprehensive Stage II. Parents are fearful of their child not surviving and, if they do, what will the neurodevelopmental outcomes be for their future. Health-care providers need to better support patients and families from the initial diagnosis, whether a fetal or postnatal diagnosis. All options need to be explained to parents free of bias. Every single-ventricle patient should be enrolled in a home monitoring program with 24/7 availability and access to support from the single-ventricle cardiac team, as this is a stressful time for families. Every family needs psychosocial support and counseling. The financial burden alone warrants assistance due to frequent evaluations, echocardiograms, hospital admissions, cardiac surgeries, and interventional cardiac catheterization procedures. Family financial resources are often exhausted throughout early childhood for financial burdens do not end with the third-staged surgery. Care providers need to continue to evaluate neurodevelopment throughout childhood, providing interventions and support for patients, for the best possible outcomes.