1-Year Outcomes in a Pooled Cohort of Harmony Transcatheter Pulmonary Valve Clinical Trial Participants.

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.

Over-expansion of right ventricle to pulmonary artery conduits during transcatheter pulmonary valve placement.

OBJECTIVES: To determine the safety and feasibility of over-expansion of right ventricle to pulmonary artery conduits during transcatheter pulmonary valve placement. BACKGROUND: Transcatheter pulmonary valve placement is an alternative to surgical pulmonary valve replacement. Traditionally, it was thought to be unsafe to expand a conduit to >110% of its original size. METHODS: This retrospective cohort study from two centers includes patients with right ventricle to pulmonary artery conduits with attempted transcatheter pulmonary valve placement from 2010 to 2017. Demographic, procedural, echocardiographic and follow-up data, and complications were evaluated in control and overdilation (to >110% original conduit size) groups. RESULTS: One hundred and seventy-two patients (51 overdilation and 121 control) had attempted transcatheter pulmonary valve placement (98% successful). The overdilation group was younger (11.2 versus 16.7 years, p < 0.001) with smaller conduits (15 versus 22 mm, p < 0.001); however, the final valve size was not significantly different (19.7 versus 20.2 mm, p = 0.2). Baseline peak echocardiographic gradient was no different (51.8 versus 55.6 mmHg, p = 0.3). Procedural complications were more frequent in overdilation (18%) than control (7%) groups (most successfully addressed during the procedure). One patient from each group required urgent surgical intervention, with no procedural mortality. Follow-up echocardiographic peak gradients were similar (24.1 versus 26 mmHg, p = 0.5). CONCLUSIONS: Over-expansion of right ventricle to pulmonary artery conduits during transcatheter pulmonary valve placement can be performed successfully. Procedural complications are more frequent with conduit overdilation, but there was no difference in the rate of life-threatening complications. There was no difference in valve function at most recent follow-up, and no difference in rate of reintervention. The long-term outcomes of transcatheter pulmonary valve placement with conduit over-expansion requires further study.

Ventricular arrhythmias following balloon-expandable transcatheter pulmonary valve replacement in the native right ventricular outflow tract.

BACKGROUND: Ventricular arrhythmia incidence in children and adolescents undergoing transcatheter pulmonary valve replacement (TPVR) within the native right ventricular outflow tract (nRVOT) is unknown. We sought to describe the incidence, severity, and duration of ventricular arrhythmias and identify associated risk factors in this population. METHODS: This was a retrospective cohort study of 78 patients <21 years of age who underwent TPVR within the nRVOT. Patients were excluded for pre-existing ventricular arrhythmia or antiarrhythmic use. Study variables included surgical history, valve replacement indication, valve type/size, and ventricular arrhythmia. Univariable logistic regression models were used to evaluate factors associated with ventricular arrhythmias, followed by subset analyses. RESULTS: Nonsustained ventricular arrhythmia occurred in 26/78 patients (33.3%). The median age at the procedure was 10.3 years (interquartle range [IQR]: 6.5, 12.8). Compared with other nRVOT types, surgical repair with transannular patch was protective against ventricular arrhythmia incidence: odds ratio (OR): 0.35 (95% confidence interval [CI], 0.13-0.95). Patient weight, valve type/size, number of prestents, and degree of stent extension into the RVOT were not associated with ventricular arrhythmia occurrence. Beta blocker was started in 16/26 (61.5%) patients with ventricular arrhythmia. One additional patient was lost to follow-up. The median beta blocker duration was 46 days (IQR 42, 102). Beta blocker was discontinued in 10 patients by 8-week follow-up and in the remaining four by 9 months. CONCLUSIONS: Though common after balloon-expandable TPVR within the nRVOT, ventricular arrhythmias were benign and transient. Antiarrhythmic medications were successfully discontinued in the majority at 6- to 8-week follow-up, and in all patients by 20 months.

Transcatheter and Surgical Aortic Valve Implantation in Children, Adolescents, and Young Adults With Congenital Heart Disease.

Transcatheter aortic valve implantation (TAVI) is common in adults but rare in children and adolescents. Since 2014, our institution has incorporated a transcatheter approach as an option for aortic valve replacement in this population. The purpose of this study was to compare short-term outcomes of TAVI with surgical aortic valve replacement (SAVR). This single-center, retrospective study included patients aged 10 to 21 years who had a native SAVR or TAVI between January 2010 to April 2020. Comparative analysis of baseline characteristics and a composite outcome (stroke within 6 months, readmission within 30 days, death) between SAVR and TAVI were made using chi-square test or Wilcoxon rank sum test, as appropriate. Of the 77 patients who underwent native aortic valve implantation during the study period (60 SAVR, 17 TAVI), 46 were aged 10 to 21 years (30 SAVR, 16 TAVI). Median follow-up was 3.8 years (interquartile range 1.5 to 4.9) for the SAVR group and 1.5 years (interquartile range 1.1 to 1.2) for the TAVI group. There was no difference in the composite outcome between groups. Patients in the SAVR group were more likely to have undergone concomitant surgical intervention and have longer intensive care unit and hospital stays. In conclusion, our study suggests similar short-term outcomes between SAVR and TAVI in children and young adults aged 10 to 21 years. Longer-term studies are essential to understand the utility of TAVI and to better consider the option of a transcatheter approach as an alternative to SAVR in the pediatric population.

Short-Term Left Ventricular Reverse Remodeling after Transcatheter Aortic Valve Replacement in Children.

BACKGROUND: There are no published data on left ventricular (LV) reverse remodeling after transcatheter aortic valve replacement (TAVR) in children. The aim of this study was to assess changes in LV echocardiographic parameters 6 months after TAVR in children. METHODS: This single-center, retrospective study included all 22 patients (age < 21 years) who underwent TAVR. The median age was 14.7 years (interquartile range, 13.3-15.9 years), median weight was 57 kg (interquartile range, 46.0-66.3 kg), and 59% of patients were male. Demographics, type and duration of aortic valve dysfunction, symptom and treatment data, and preprocedural and 6-month follow-up echocardiographic data (LV volume, mass, end-diastolic dimension, end-systolic dimension, ejection fraction [EF], sphericity, and longitudinal strain) were collected. Failure to reverse remodel at 6 months was defined as meeting at least two of the following: Z score ≥ 2 that was unchanged or increased from baseline for LV volume, mass, end-diastolic dimension, or end-systolic dimension; abnormally high sphericity index that was unchanged or increased; and abnormally low EF or longitudinal strain. Median, interquartile range, and range are reported for continuous variables, and pre- and post-TAVR data were compared using the Wilcoxon signed rank test. RESULTS: Eight patients (36%) had isolated aortic stenosis, four (18%) had isolated regurgitation, and 10 had (46%) mixed disease. Twelve (55%) had symptoms and 20 (91%) had prior surgical or catheter valve interventions. The primary complication was left bundle branch block, occurring in four children (18%). At 6 months, LV volume, mass, end-diastolic dimension, end-systolic dimension, and sphericity index improved. EF and strain were normal at baseline and at follow-up. Of three patients who failed to reverse remodel, two had left bundle branch block. Of three patients with persistent symptoms, one had failure of reverse remodeling. CONCLUSIONS: Most pediatric patients had evidence of reverse LV remodeling 6 months after TAVR, suggesting a possible alternative to surgical aortic valve replacement in this population. Functional parameters (EF and strain) were normal at baseline and follow-up. Future studies are needed to determine optimal timing of TAVR and to explore the association of postprocedural left bundle branch block on failed reverse remodeling and outcomes in this population.

Echocardiographic Assessment of Melody Versus Sapien Valves Following Transcatheter Pulmonary Valve Replacement.

OBJECTIVES: The aim of this study was to compare the immediate and midterm echocardiographic performance of the Melody (Medtronic Inc) and Sapien (Edwards Lifesciences Inc) valves after transcatheter pulmonary valve replacement (TPVR) in native and conduit right ventricular outflow tracts (RVOTs). BACKGROUND: TPVR is now a common procedure, but limited data exist comparing postimplantation echocardiographic findings between Melody and Sapien valves. METHODS: This was a single-institution retrospective cohort study of all patients who underwent successful TPVR from 2011 to 2020. Patient demographics, procedural details, and immediate and midterm echocardiographic findings were collected and compared between valve types using the Wilcoxon rank sum, chi-square, or Fisher exact test as appropriate. Subgroups were analyzed individually and were adjusted for multiple comparisons using the Bonferroni method. RESULTS: A total of 328 patients underwent successful TPVR (Melody: n = 202, Sapien: n = 126). The groups had a similar baseline age, weight, and diagnosis. The most common indications for TPVR were pulmonary stenosis (32.2%) or mixed disease (46%) in the Melody group and pulmonary insufficiency in the Sapien group (52.4%) (P < 0.001). Sapien valves were more often placed in native RVOTs (43.7% vs 18.8%; P < 0.001). The discharge and follow-up mean and peak Doppler gradients were similar between the Melody and Sapien groups. Valves implanted in native RVOTs had significantly lower postimplantation gradients at each follow-up period. CONCLUSIONS: Echocardiographic performance after TPVR was generally acceptable and similar when comparing Melody and Sapien valves despite differences in the indication and anatomy in each group. The peak and mean gradients were lower in transcatheter valves implanted in native RVOTs compared with those implanted in conduits or bioprosthetic valves.

Comparison of the investigational device exemption and post-approval trials of the Melody transcatheter pulmonary valve.

OBJECTIVE: We compared 5-year outcomes of transcatheter pulmonary valve (TPV) replacement with the Melody TPV in the post-approval study (PAS) and the investigational device exemption (IDE) trial. BACKGROUND: As a condition of approval of the Melody TPV after the IDE trial, the Food and Drug Administration required that a PAS be conducted to evaluate outcomes of TPV replacement in a "real-world" environment. The 5-year outcomes of the PAS have not been published, and the IDE and PAS trials have not been compared. METHODS: The cohorts comprised all patients catheterized and implanted at 5 IDE sites and 10 PAS sites. Differences in trial protocols were detailed. Time-related outcomes and valve-related adverse events were compared between the two trials with Kaplan-Meier curves and log-rank testing. RESULTS: 167 patients (median age, 19 years) were catheterized and 150 underwent TPV replacement in the IDE trial; 121 were catheterized (median age, 17 years) and 100 implanted in the PAS. Freedom from hemodynamic dysfunction (p = .61) or any reintervention (p = .74) over time did not differ between trials. Freedom from stent fracture (p = .003) and transcatheter reintervention (p = .010) were longer in PAS, whereas freedom from explant (p = .020) and TPV endocarditis (p = .007) were shorter. Clinically important adverse events (AEs) were reported in 14% of PAS and 7.2% of IDE patients (p = .056); the incidence of any particular event was low in both. CONCLUSIONS: Hemodynamic and time-related outcomes in the PAS and IDE trials were generally similar, confirming the effectiveness of the Melody TPV with real-world providers. There were few significant complications and limited power to identify important differences in AEs. The lack of major differences in outcomes between the two studies questions the usefulness of mandated costly post-approval studies as part of the regulatory process for Class III medical devices.

ASSURED clinical study: New GORE® CARDIOFORM ASD occluder for transcatheter closure of atrial septal defect.

OBJECTIVE: Assess clinical performance of a new device for transcatheter closure of atrial septal defect (ASD). BACKGROUND: Previously-approved ASD Closure devices have known limitations. Device erosion has been associated with the AMPLATZER® septal occluder in patients with retro-aortic rim deficiency (<5 mm), while defects ≥18 mm are too large for the GORE® CARDIOFORM septal occluder. The GORE® CARDIOFORM ASD occluder (GCA), a hybrid of the approved devices, was designed to expand the eligible ASD population. METHODS: One-hundred and twenty-five ASD patients were enrolled in a prospective, multicenter registry. Descriptive clinical endpoints included: technical implant success, closure success, serious adverse events (SAE), clinically significant new arrhythmia, and wire frame fracture. Procedural outcomes and adverse events were adjudicated by an Echocardiography Core Lab and Independent Data Review Board, respectively. RESULTS: Median subject age was 12.3 years (range 2.9-84.7), with 72% of patients ≤18 years old. Median ASD stop-flow diameter was 17.0 mm (8.0-30.0), with 43% ≥18 mm. Deficient retro-aortic rim occurred in 57% of subjects, and 30% had both diameter ≥ 18 mm and deficient rim. Technical Implant Success was achieved in 120/125 (96%), though three devices were removed within 24 hr. At the scheduled 6-month evaluation, 112/117 returned for evaluation. All 112 had closure success. SAE occurred in 6/125 (4.8%) and 6/125 (4.8%) had clinically significant new arrhythmia. Wire frame fractures occurred in 37/104 (36%), without any associated clinical sequelae, residual shunt, or device instability. CONCLUSION: The GCA performed effectively and safely in this initial cohort, and led to FDA approval based on this data.

Relationship Between Time to Left Atrial Decompression and Outcomes in Patients Receiving Venoarterial Extracorporeal Membrane Oxygenation Support: A Multicenter Pediatric Interventional Cardiology Early-Career Society Study.

OBJECTIVES: To assess the variation in timing of left atrial decompression and its association with clinical outcomes in pediatric patients supported with venoarterial extracorporeal membrane oxygenation across a multicenter cohort. DESIGN: Multicenter retrospective study. SETTING: Eleven pediatric hospitals within the United States. PATIENTS: Patients less than 18 years on venoarterial extracorporeal membrane oxygenation who underwent left atrial decompression from 2004 to 2016. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: A total of 137 patients (median age, 4.7 yr) were included. Cardiomyopathy was the most common diagnosis (47%). Cardiac arrest (39%) and low cardiac output (50%) were the most common extracorporeal membrane oxygenation indications. Median time to left atrial decompression was 6.2 hours (interquartile range, 3.8-17.2 hr) with the optimal cut-point of greater than or equal to 18 hours for late decompression determined by receiver operating characteristic curve. In univariate analysis, late decompression was associated with longer extracorporeal membrane oxygenation duration (median 8.5 vs 5 d; p = 0.02). In multivariable analysis taking into account clinical confounder and center effects, late decompression remained significantly associated with prolonged extracorporeal membrane oxygenation duration (adjusted odds ratio, 4.4; p = 0.002). Late decompression was also associated with longer duration of mechanical ventilation (adjusted odds ratio, 4.8; p = 0.002). Timing of decompression was not associated with in-hospital survival (p = 0.36) or overall survival (p = 0.42) with median follow-up of 3.2 years. CONCLUSIONS: In this multicenter study of pediatric patients receiving venoarterial extracorporeal membrane oxygenation, late left atrial decompression (≥ 18 hr) was associated with longer duration of extracorporeal membrane oxygenation support and mechanical ventilation. Although no survival benefit was demonstrated, the known morbidities associated with prolonged extracorporeal membrane oxygenation use may justify a recommendation for early left atrial decompression.

Implantation of the Melody transcatheter pulmonary valve PB1016 in patients with dysfunctional right ventricular outflow tract conduits.

OBJECTIVES: This study describes procedural and 1-year outcomes of the 16 mm Melody PB1016 valve in patients with dysfunctional RVOT conduits. BACKGROUND: The Melody PB1016 is a standard Melody valve produced from a 16 mm bovine jugular vein and is intended for deployment up to 20 mm. METHODS: This is a prospective, non-randomized, multicenter study of the procedural and short-term outcomes of Melody PB1016 TPV replacement within dysfunctional RVOT conduits. Data from eight centers were included in the analysis. RESULTS: During the study period, 39 patients underwent attempted Melody TPVR. Of the 39 patients, 30 underwent successful Melody TPVR. The majority of patients underwent placement of one or more stents prior to TPVR. There was a significant reduction in peak conduit pressure gradient following TPVR (38 mmHg vs. 11 mmHg, P < 0.001). There were three cases of confined conduit tears successfully treated with covered stents or the valve itself. Repeat catheterization was performed in one patient for early re-obstruction that was successfully treated with balloon valvuloplasty. At recent follow-up, there were no cases of more than mild valve regurgitation and the mean pulmonary valve gradient by echocardiogram remained reduced relative to pre-TPVR implant measurements (33.5 mmHg vs. 15.2 mmHg). There were no cases of valve stent fracture or endocarditis reported at the 1-year follow-up. CONCLUSIONS: Our analysis of TPVR with the PB1016 valve in RVOT conduits showed it to be safe and effective and can be performed in a wide range of conduit sizes with preserved valve function. ClinicalTrials.gov Identifier: NCT02347189.

Endocarditis After Transcatheter Pulmonary Valve Replacement.

BACKGROUND: Endocarditis has emerged as one of the most concerning adverse outcomes in patients with congenital anomalies involving the right ventricular outflow tract (RVOT) and prosthetic valves. OBJECTIVES: The aim of this study was to evaluate rates and potential risk factors for endocarditis after transcatheter pulmonary valve replacement in the prospective Melody valve trials. METHODS: All patients in whom a transcatheter pulmonary valve (TPV) was implanted in the RVOT as part of 3 prospective multicenter studies comprised the analytic cohort. The diagnosis of endocarditis and involvement of the TPV were determined by the implanting investigator. RESULTS: A total of 309 patients underwent transcatheter pulmonary valve replacement (TPVR) and were discharged with a valve in place. The median follow-up duration was 5.1 years, and total observation until study exit was 1,660.3 patient-years. Endocarditis was diagnosed in 46 patients (median 3.1 years after TPVR), and a total of 35 patients were reported to have TPV-related endocarditis (34 at the initial diagnosis, 1 with a second episode). The annualized incidence rate of endocarditis was 3.1% per patient-year and of TPV-related endocarditis was 2.4% per patient-year. At 5 years post-TPVR, freedom from a diagnosis of endocarditis was 89% and freedom from TPV-related endocarditis was 92%. By multivariable analysis, age ≤12 years at implant (hazard ratio: 2.3; 95% confidence interval: 1.2 to 4.4; p = 0.011) and immediate post-implant peak gradient ≥15 mm Hg (2.7; 95% confidence interval: 1.4 to 4.9; p = 0.002) were associated with development of endocarditis and with development of TPV-related endocarditis (age ≤12 years: 2.8; 95% confidence interval: 1.3 to 5.7; p = 0.006; gradient ≥15 mm Hg: 2.6; 95% confidence interval: 1.3 to 5.2; p = 0.008). CONCLUSIONS: Endocarditis is an important adverse outcome following TVPR in children and adults with post-operative congenital heart disease involving the RVOT. Ongoing efforts to understand, prevent, and optimize management of this complication are paramount in making the best use of TPV therapy. (Melody Transcatheter Pulmonary Valve [TPV] Study: Post Approval Study of the Original Investigational Device Exemption [IDE] Cohort; NCT00740870; Melody Transcatheter Pulmonary Valve Post-Approval Study; NCT01186692; and Melody Transcatheter Pulmonary Valve [TPV] Post-Market Surveillance Study; NCT00688571).

Safety and Feasibility of Melody Transcatheter Pulmonary Valve Replacement in the Native Right Ventricular Outflow Tract: A Multicenter Pediatric Heart Network Scholar Study.

OBJECTIVES: This study sought to determine the safety and feasibility of transcatheter pulmonary valve replacement (TPVR) using the Melody valve in native (nonconduit) right ventricular outflow tracts (nRVOT), and to identify factors associated with successful TPVR. BACKGROUND: The Melody valve is Food and Drug Administration-approved for TPVR within right ventricle-to-pulmonary artery conduits and bioprosthetic pulmonary valves. However, most patients needing pulmonary valve replacement have nRVOT and TPVR has been adapted for this indication. METHODS: In this multicenter retrospective study of all patients presenting for nRVOT TPVR, we collected pre-procedural magnetic resonance imaging, echocardiography, and catheterization data, and evaluated procedural and early outcomes. RESULTS: Of 229 patients (age 21 ± 15 years from 11 centers), 132 (58%) had successful TPVR. In the remaining 97, TPVR was not performed, most often because of prohibitively large nRVOT (n = 67) or compression of the aortic root or coronary arteries (n = 18). There were no deaths and 5 (4%) serious complications, including pre-stent embolization requiring surgery in 4 patients, and arrhythmia in 1. Higher pre-catheterization echocardiographic RVOT gradient was associated with TPVR success (p = 0.001) and larger center volume approached significance (p = 0.08). Magnetic resonance imaging anterior-posterior and lateral RVOT diameters were smaller in implanted versus nonimplanted patients (18.0 ± 3.6 mm vs. 20.1 ± 3.5 mm; p = 0.005; 18.4 ± 4.3 mm vs. 21.5 ± 3.8 mm; p = 0.002). CONCLUSIONS: TPVR in the nRVOT was feasible and safe. However, nearly half the patients presenting for catheterization did not undergo TPV implantation, mainly because of prohibitively large nRVOT size. Improved understanding of magnetic resonance imaging data and availability of larger devices may improve the success rate for nRVOT TPVR.

Pulmonary Valve Replacement: A Single-Institution Comparison of Surgical and Transcatheter Valves.

BACKGROUND: Transcatheter pulmonary valve replacement (TPVR) is increasingly utilized to address residual or recurrent right ventricular outflow tract pathology in congenital heart disease patients. We aimed to evaluate clinical outcomes and resource utilization comparing TPVR to surgical pulmonary valve replacement (SPVR) for this patient population. METHODS: From January 2010 until December 2015, 224 patients underwent pulmonary valve replacement (SPVR = 100 and TPVR = 124). These groups were assessed and compared for survival, reoperation, reintervention (surgical or catheter based), hospital costs, and hemodynamic performance. RESULTS: There were no mortalities in either group. Despite SPVR patients being significantly younger (12 ± 7 years of age versus 19 ± 13 years of age; p < 0.001) and smaller (body surface area 1.2 ± 0.5 m2 versus 1.4 ± 0.5 m2; p < 0.001), they had similar median valve size implanted (23 mm [interquartile range, 21 to 27 mm) versus 22 mm [interquartile range, 20 to 22 mm]). There was no difference in the adjusted peak gradient (SPVR 24.1 ± 15.1 mm Hg versus TPVR 20.7 ± 11.4 mm Hg; p = 017) at last follow-up. Cumulative freedom from reintervention at 4 years was similar between groups (p = 0.98). TPVR could not be placed in 34 patients either due to coronary compression or excessive outflow tract diameter. SPVR patients had longer hospital length of stay (4.1 ± 1.8 days versus 1.2 ± 0.7 days; p < 0.001). TPVR patients had higher rates of infective endocarditis (4.8% versus 0%; p < 0.001) and overall hospital costs ($57,221 ± $13091 versus $44,366 ± $16,519; p < 0.001). CONCLUSIONS: Hemodynamic performance is similar between SPVR and TPVR with similar rates of reintervention. While SPVR patients have a longer hospital length of stay, TPVR was associated with higher rates of infective endocarditis, hospital costs, and failure to implant.

Transcatheter Pulmonary Valve Replacement With the Melody Valve in Small Diameter Expandable Right Ventricular Outflow Tract Conduits.

OBJECTIVES: This study sought to evaluate the safety, feasibility, and outcomes of transcatheter pulmonary valve replacement (TPVR) in conduits ≤16 mm in diameter. BACKGROUND: The Melody valve (Medtronic, Minneapolis, Minnesota) is approved for the treatment of dysfunctional right ventricular outflow tract (RVOT) conduits ≥16 mm in diameter at the time of implant. Limited data are available regarding the use of this device in smaller conduits. METHODS: The study retrospectively evaluated patients from 9 centers who underwent percutaneous TPVR into a conduit that was ≤16 mm in diameter at the time of implant, and reported procedural characteristics and outcomes. RESULTS: A total of 140 patients were included and 117 patients (78%; median age and weight 11 years of age and 35 kg, respectively) underwent successful TPVR. The median original conduit diameter was 15 (range: 9 to 16) mm, and the median narrowest conduit diameter was 11 (range: 4 to 23) mm. Conduits were enlarged to a median diameter of 19 mm (29% larger than the implanted diameter), with no difference between conduits. There was significant hemodynamic improvement post-implant, with a residual peak RVOT pressure gradient of 7 mm Hg (p < 0.001) and no significant pulmonary regurgitation. During a median follow-up of 2.0 years, freedom from RVOT reintervention was 97% and 89% at 2 and 4 years, respectively, and there were no deaths and 5 cases of endocarditis (incidence rate 2.0% per patient-year). CONCLUSIONS: In this preliminary experience, TPVR with the Melody valve into expandable small diameter conduits was feasible and safe, with favorable early and long-term procedural and hemodynamic outcomes.

Percutaneous transcatheter pulmonary valve replacement in children weighing less than 20 kg.

BACKGROUND: Since FDA approval of the Melody valve, transcatheter pulmonary valve replacement (TPVR) has been offered to an expanding population. Limited data exist regarding the safety and feasibility of TPVR in smaller patients. METHODS: All patients weighing <20 kg who underwent catheterization for percutaneous TPVR at four centers were reviewed. RESULTS: Of the 51 patients reviewed, 43 (84%) had successful valve implantation and 8 (16%) were found not to be candidates due to access veins too small (n = 3), coronary artery/aortic root compression (n = 3), and RVOT too large (n = 2). The 43 patients who underwent successful percutaneous TPVR had a median age and weight of 5.8 years (3.3-10) and 17.7 kg (13.5-19.8), and most had tetralogy of Fallot (TOF). TPVR was performed via femoral vein (FV) access in 24 patients and internal jugular vein (IJV) access in 19 patients. Median weight in patients with IJV implant was 1.1 kg lower than those who underwent transfemoral implant (17.0 vs. 18.1 kg, P = 0.05). There were four adverse events: one iliac vein injury, one contained MPA tear, and two patients with post-procedure femoral vein bleeding. All patients were alive at recent follow-up, a median of 2.0 years (0.1-6.0) after TPVR. There was excellent valve function with mean Doppler gradients of 3-20 mm Hg, and trivial or mild pulmonary regurgitation in all but one patient. There were no RVOT reinterventions and no cases of endocarditis. CONCLUSIONS: Percutaneous TPVR can be safely performed in patients <20 kg. The procedure frequently requires IJV access, and access site/bleeding complications may be more common in this cohort.

Serial Versus Direct Dilation of Small Diameter Stents Results in a More Predictable and Complete Intentional Transcatheter Stent Fracture: A PICES Bench Testing Study.

Balloon-expandable stents, implanted in infants and children with congenital heart disease (CHD), often require redilation to match somatic growth. Small diameter stents may eventually require longitudinal surgical transection to prevent iatrogenic vascular stenosis. Intentional transcatheter stent fracture (TSF) is an emerging alternative approach to stent transection, but little is known about the optimal stent substrate and best protocol to improve the likelihood of successful TSF. Bench testing was performed with a stent dilation protocol. After recording baseline characteristics, stents were serially or directly dilated using ultra-high-pressure balloons (UHPB) until fracture occurred or further stent dilation was not possible. Stent characteristics recorded were as follows: cell design, metallurgy, mechanism, and uniformity of fracture. Stents tested included bare-metal coronary stents, premounted small diameter stents, and ePTFE-covered small diameter premounted stents. Ninety-four stents representing 9 distinct models were maximally dilated, with 80 (85%) demonstrating evidence of fracture. Comprehensive fracture details were recorded in 64 stents: linear and complete in 34/64 stents (53.1%), linear and incomplete in 9/64 stents (14.1%), transverse/complex and complete in 6/64 stents (9.4%), and transverse/complex and incomplete in 15/64 stents (23.4%). Stent fracture was not accomplished in some stent models secondary to significant shortening, i.e., "napkin-ring" formation. Serial dilation resulted in evidence of fracture in 62/67 (92.5%) stents compared with 18/27 (66.7%) stents in the direct dilation group (p = 0.003). Intentional TSF is feasible in an ex vivo model. Serial dilation more reliably expanded the stent and allowed for ultimate stent fracture, whereas direct large diameter dilation of stents was more likely to generate a "napkin-ring" configuration, which may be more resistant to fracture. In vivo animal and human testing is necessary to better understand the response to attempted TSF for newly developed stents as well as those currently in use.

Relationships Among Conduit Type, Pre-Stenting, and Outcomes in Patients Undergoing Transcatheter Pulmonary Valve Replacement in the Prospective North American and European Melody Valve Trials.

OBJECTIVES: This study sought to evaluate the incidence of and risk factors for conduit and stent-related outcomes following transcatheter pulmonary valve replacement (TPVR). BACKGROUND: Stent fracture (SF) and right ventricular outflow tract (RVOT) reintervention are among the most important adverse outcomes after TPVR using the Melody valve (Medtronic, Minneapolis, Minnesota). The conduit environment and conduit preparation practices vary among patients who undergo TPVR. METHODS: Data from 3 prospective Melody valve multicenter studies were pooled and analyzed. All patients who had successful implant of a Melody valve that was present at hospital discharge comprised the study cohort; patients who had TPVR into a stentless conduit comprised the analysis cohort. SF was diagnosed using protocol-specified or clinical fluoroscopy or radiography, and classified as major or minor. RESULTS: Of 358 patients who underwent catheterization with intent to perform TPVR, 309 were discharged with the Melody valve in place (study cohort) of which 251 patients had TPVR into a stentless conduit (analysis cohort). Median follow-up was 5 years. New pre-stents were placed in 68% of patients with a stentless conduit, and 22% received multiple pre-stents. At 3 years, freedom from any SF and major SF was 74 ± 3% and 85 ± 2%, respectively, and freedom from RVOT reintervention was 85 ± 2%. New pre-stents were associated with longer freedom from SF and RVOT reintervention than was no pre-stent. CONCLUSIONS: Risks of SF and reintervention after TPVR with a Melody valve were reduced by implantation of pre-stents, which has become standard practice. This study supports pre-stenting as an important component of TPVR therapy.

Acute and mid-term outcomes of stent implantation for recurrent coarctation of the aorta between the Norwood operation and fontan completion: A multi-center Pediatric Interventional Cardiology Early Career Society Investigation.

OBJECTIVES: We sought to evaluate outcomes of stent implantation (SI) for recurrent coarctation of the aorta (RC) following the Norwood operation. BACKGROUND: RC is common following the Norwood operation. Balloon angioplasty (BA) is standard treatment but may result in unsatisfactory relief of RC. SI may improve RC, but outcome data are limited. METHODS: We performed a multi-center retrospective study of patients who underwent SI for RC between the Norwood operation and Fontan completion. Outcomes were examined, including procedural success, serious adverse events (SAE), and freedom from re-intervention. A core laboratory was utilized to review angiograms. Coarctation Index (CI) was calculated before and after SI. Paired t-test and Wilcoxon signed-rank test were used to compare pre- and post-SI variables. RESULTS: Thirty-three patients at 8 centers underwent SI for RC at a median age of 5 months (IQR 4.1, 13.3) and weight of 5.9 kg (5.2, 8.6). Aortic arch gradient improved from 20 (15, 24) to 0 (0, 2) mmHg following SI (P < 0.0001). The median CI improved from 0.54 (0.43, 0.62) to 0.97 (0.89, 1.06) following SI (P < 0.0001). There were no procedural deaths but SAEs occurred in 12 (36%) patients. During a median follow-up duration of 29.7 months (6.8, 48.0), freedom from death or heart transplant was 82%, and from re-intervention was 45%, with median time to re-intervention of 20.1 months (11.4, 40.3). CONCLUSIONS: SI for treatment of RC in patients after the Norwood operation provides excellent acute relief of obstruction. Intraprocedural hemodynamic instability is common and re-intervention is frequent at mid-term follow-up.

Acute and midterm results following perventricular device closure of muscular ventricular septal defects: A multicenter PICES investigation.

OBJECTIVES: To describe acute and mid-term results of hybrid perventricular device closure of muscular ventricular septal defects (mVSDs). BACKGROUND: Perventricular device closure of mVSDs can mitigate technical limitations of percutaneous closure and need for cardiopulmonary bypass or ventriculotomy with a surgical approach. METHODS: This is a multicenter retrospective cohort study of patients undergoing hybrid perventricular mVSD device closure from 1/2004 to 1/2014. Procedural details, adverse events, outcomes, and follow-up data were collected. Patients were divided into two groups: (1) simple (mVSD closure alone) and (2) complex (mVSD closure with concomitant cardiac surgery). RESULTS: Forty-seven patients (60% female) underwent perventricular mVSD device closure at a median age of 5.2 months (IQR 1.8-8.9) and weight of 5.1 kg (IQR 4.0-6.9). Procedural success was 91% [100% (n = 22) simple and 84% (n = 21/25) complex]. Adverse events occurred in 19% (9/47) [9% (2/22) simple and 28% (7/25) complex]. Hospital length of stay (LOS) was shorter in the simple vs. complex group (4 vs. 14 days, P < 0.01). At mid-term follow-up of 19.2 months (IQR 2.3-43) 90% of pts had complete mVSD closure; none developed late heart block, increased atrioventricular (AV) valve insufficiency or ventricular dysfunction. CONCLUSIONS: Perventricular device closure of simple mVSD was associated with a high rate of procedural success, few adverse events, and short hospital LOS. Procedural adverse events were associated with the presence of concomitant complex surgery. Residual mVSD, AV valve insufficiency, or ventricular dysfunction were uncommon at mid-term follow-up. © 2017 Wiley Periodicals, Inc.