Simultaneous stent implantation for pulmonary artery bifurcation stenosis in infants.

OBJECTIVES: Pulmonary artery (PA) bifurcation stenosis often requires simultaneous stent placement, which may be technically challenging. Limited data exist regarding this practice in infants. We aim to report the procedural outcomes and safety of bifurcation stent placement in infants. METHODS: We performed a single-center retrospective review of infants younger than 12 months who underwent simultaneous stent placement for PA bifurcation stenosis from January 1, 2001 through December 31, 2019. RESULTS: Seventeen infants underwent simultaneous PA bifurcation stent placement. The median age was 6.4 months (1.1-10.1 months), and weight was 5.8 kg (3-10.6 kg). Nine (52.9%) patients had had prior PA intervention. Most stents were placed in central PAs (28, 82.4%), followed by lobar branches (6, 17.6%). All patients received pre-mounted stents. The peak gradient across each branch decreased from 47.4 ± 16 to 18.7 ± 13 mm Hg (P less than .0001). The right ventricle to systemic systolic pressure ratio decreased from systemic (1.0 ± 0.3) to just over half systemic (0.58 ± 0.2) (P = .0001). The minimum vessel diameter increased from 3.6 ± 1.5 to 6.0 ± 1.9 mm (P less than .0001). There were 4 (23.5%) patients with high severity adverse events. There were no procedure-related deaths. The median follow-up period was 83.8 months (5.3 months-19.4 years). All patients had subsequent PA re-intervention at a median time of 8.1 months (2.9 months-8.8 years), and median time to re-operation was 19.1 months (2.9 months-7.5 years). CONCLUSIONS: Simultaneous PA stent placement is an effective strategy for relief of bifurcation stenosis in infants. Future transcatheter interventions are necessary to account for patient growth, but may delay the need for re-operation.

Outcomes and Risk Factors of Interventions for Pediatric Post-operative Pulmonary Vein Stenosis.

Pulmonary vein stenosis (PVS) in children is a challenging condition with poor outcomes. Post-operative stenosis can occur after repair of anomalous pulmonary venous return (APVR) or stenosis within native veins. There is limited data on the outcomes of post-operative PVS. Our objective was to review our experience and assess surgical and transcatheter outcomes. Single-center retrospective study was performed including patients < 18 years who developed restenosis after baseline pulmonary vein surgery that required additional intervention(s) from 1/2005 to 1/2020. Non-invasive imaging, catheterization and surgical data were reviewed. We identified 46 patients with post-operative PVS with 11 (23.9%) patient deaths. Median age at index procedure was 7.2 months (range 1 month-10 years), and median follow-up was 10.8 months (range 1 day-13 years). Index procedure was surgical in 36 (78.3%) and transcatheter in 10 (21.7%). Twenty-three (50%) patients developed vein atresia. Mortality was not associated with number of affected veins, vein atresia, or procedure type. Single ventricle physiology, complex congenital heart disease (CCHD), and genetic disorders were associated with mortality. Survival rate was higher in APVR patients (p = 0.03). Patients with three or more interventions had a higher survival rate compared to patients with 1-2 interventions (p = 0.02). Male gender, necrotizing enterocolitis, and diffuse hypoplasia were associated with vein atresia. In post-operative PVS, mortality is associated with CCHD, single ventricle physiology, and genetic disorders. Vein atresia is associated with male gender, necrotizing enterocolitis, and diffuse hypoplasia. Multiple repeated interventions may offer a patient survival benefit; however, larger prospective studies are necessary to elucidate this relationship further.

Use of the Inspiris valve in the native right ventricular outflow tract is associated with early prosthetic regurgitation.

OBJECTIVE: The Inspiris Resilia prosthesis (Edwards Lifesciences) has been increasingly used in the pulmonic position with limited performance data. We sought to investigate its durability as a surgical pulmonary valve replacement (PVR). METHODS: We retrospectively reviewed patients who underwent PVR or conduit replacement with an Inspiris or non-Inspiris valve/conduit from 2018 to 2022. The primary end point was freedom from a composite of at least moderate pulmonary regurgitation, pulmonary stenosis, or valve/conduit reintervention. Secondary end points were individual components of the composite outcome. To account for baseline differences, propensity matching identified 70 patient pairs. RESULTS: A total of 227 patients (median age: 19.3 years [interquartile range, 11.8-34.4]) underwent PVR or conduit replacement (Inspiris: n = 120 [52.9%], non-Inspiris: n = 107 [47.1%]). Median follow-up was 26.6 months [interquartile range, 12.4-41.1]. Among matched patients, 2-year freedom from valve failure was lower in the Inspiris group (53.5 ± 9.3% vs 78.5 ± 5.9%, P = .03), as was freedom from at least moderate pulmonary regurgitation (54.2 ± 9.6% vs 86.4 ± 4.9%, P < .01). There was no difference in 2-year freedom from at least moderate pulmonary stenosis (P = .61) or reintervention (P = .92). Inspiris durability was poorer when implanted in the native right ventricular outflow tract compared with as a conduit, with 18-month freedom from valve failure of 59.0 ± 9.5% versus 85.9 ± 9.5% (P = .03). CONCLUSIONS: Early durability of the Inspiris valve is poor when implanted in the native right ventricular outflow tract; its unique design may be incompatible with the compliant pulmonary root. Modified implantation techniques or alternative prostheses should be considered.

Right Ventricular Strain in Patients With Ductal-Dependent Tetralogy of Fallot.

BACKGROUND: Right ventricular (RV) dysfunction is an independent predictor of poor outcomes in patients with tetralogy of Fallot (TOF), and global longitudinal strain (GLS) is a well-validated echocardiographic technique to measure RV function. Although trends in RV GLS have been examined in patients with TOF, they have not been studied specifically in those with ductal-dependent TOF, a group in which there is not a clear consensus on the best surgical strategy. The aim of this study was to assess the midterm trajectory of RV GLS in patients with ductal-dependent TOF, drivers of this trajectory, and differences in RV GLS between repair strategies. METHODS: This was a retrospective two-center cohort study of patients with ductal-dependent TOF who underwent repair. Ductal dependence was defined as being initiated on prostaglandin therapy and/or undergoing surgical intervention on or before 30 days of life. RV GLS was measured on echocardiography preoperatively, early after complete repair, and at 1 and 2 years of age. RV GLS was trended over time and compared between surgical strategies and with control subjects. Mixed-effects linear regression models were used to evaluate the factors associated with changes in RV GLS over time. RESULTS: Forty-four patients with ductal-dependent TOF were included in the study, of whom 33 (75%) underwent primary complete repair and 11 (25%) underwent staged repair. Complete TOF repair was performed at a median of 7 days in the primary-repair group and 178 days in the staged-repair group. RV GLS improved over time from post-complete repair echocardiography through 2 years of age (-17.4% [interquartile range, -15.5% to -18.9%] vs -21.5% [interquartile range, -18.0% to -23.3%], P < .001). However, compared with age-matched control subjects, patients had worse RV GLS at all time points. There was no difference in RV GLS between the staged and primary complete repair groups at 2-year follow-up. Shorter intensive care unit length of stay after complete repair was independently associated with improvement in RV GLS over time. Strain improved by 0.07% (95% CI, 0.01 to 0.12) for each fewer day in the intensive care unit (P = .03). CONCLUSIONS: RV GLS improves over time among patients with ductal-dependent TOF, though it is consistently reduced compared with control subjects, suggesting an altered deformation pattern in patients with ductal-dependent TOF. There was no difference in RV GLS between the primary- and staged-repair groups at midterm follow-up, suggesting that repair strategy is not a risk factor for worse RV strain in the mid postoperative period. A shorter complete-repair intensive care unit length of stay is associated with an improved trajectory of RV GLS.

Ross Procedure in Neonate and Infant Populations: A Meta-Analysis Review.

OBJECTIVE: This study aims to perform a meta-analysis of early and late outcomes of the Ross/Ross-Konno procedures in neonates/infants. METHODS: A meta-analysis was performed in accordance with PRISMA guidelines. We used Ovid versions of MEDLINE/PubMed for relevant studies and included those that reported Ross/Ross-Konno operations in neonates/infants and at least one of the predetermined clinical outcomes. I2 and double arcsine methods assessed the heterogeneity between pooled estimates. We used a random-effect model to account for heterogeneity with MetaXL. We calculated point estimates of a pooled estimates along with its 95% CI. RESULTS: 587 neonate/infant patients were included with median age of 87.5 days old. The follow-up range was five days to 23 years. Early mortality reported in 25 studies with pooled estimates of 18.3% (95% CI: 13.6%-23.5%). Estimates ranged from 0% to 50% with relatively substantial heterogeneity (P = .01, I2 = 48.6%). Late mortality reported in 22 studies with pooled incidence of 9.7% (95% CI: 5.9%-14.3%). Estimates ranged from 0% to 53% with relatively substantial heterogeneity (P = .01, I2 = 46.1%). Autograft reintervention reported in 18 studies with pooled estimate of 19.2% (95% CI: 7.3%-34.5%). Estimates ranged from 0% to 81.8% with high heterogeneity (P < .001, I2 = 90.5%). Right ventricle-to-pulmonary artery conduit reintervention reported in 16 studies with pooled estimates of 32.0% (95% CI: 20.9%-44.12%). Estimates ranged from 0% to 92.3% with high heterogeneity (P < .001, I2 = 75.9%). CONCLUSIONS: The data suggest that the Ross/Ross-Konno procedure in neonates/infants still carries significant risk of early/late mortality and autograft/conduit reintervention. The high variability of results among centers confirms the need for surgical expertise and good patient selection. Prospective multicenter studies are warranted to investigate the rate of autograft reintervention and the impact on long-term survival in this specific population.

Pulmonary artery thromboembolism in a critically ill neonate successfully treated using thrombolytic therapy.

Pulmonary artery thromboembolism is a common and treatable cause of adult pulmonary hypertension. Although rare in children, if undiagnosed, it can result in significant morbidity and mortality. We report a case of a cyanotic neonate found to have bilateral pulmonary arterial thrombi who successfully underwent thrombolysis using tissue plasminogen activator with prompt resolution of right ventricular hypertension.

Non-Elective Pediatric Cardiac Catheterization During COVID-19 Pandemic: A New York Center Experience.

BACKGROUND: COVID-19 has led to major changes in hospital systems across the world. In an effort to reduce viral transmission, conserve resources, and in accordance with institutional and state mandates, all elective procedures and surgeries were postponed during the initial outbreak. Guidelines for case selection are limited and management for pediatric catheterization laboratories during this crisis is unprecedented. OBJECTIVES: To report the protocols and case selection of a high-volume pediatric cardiac catheterization laboratory in the epicenter of the novel coronavirus (COVID-19) pandemic. METHODS: All pediatric cardiac catheterization procedures from March 16, 2020 through May 10, 2020 were reviewed. Changes to case selection and periprocedural workflow are described. Data were collected on COVID-19 testing status and primary procedure type, and all procedures were classified by urgency. RESULTS: There were 52 catheterizations performed on 50 patients. Endomyocardial biopsies were the most common procedure (n = 27; 52%). Interventional and diagnostic procedures represented 27% (n = 14) and 21% (n = 11) of cases, respectively. Two emergent procedures (3.8%) were performed on patients with positive COVID-19 testing. Most cases were performed on patients with negative COVID-19 testing (n = 33; 94%). CONCLUSIONS: Adjusting to the COVID-19 pandemic in a high-volume pediatric cardiac catheterization laboratory can be safely and effectively managed by prioritizing emergent and urgent cases and modifying workflow operations. The experience of this center may assist other pediatric cardiac catheterization laboratories in adapting to similar practice changes as the pandemic continues to evolve.

Comparison of computed tomography angiography versus cardiac catheterization for preoperative evaluation of major aortopulmonary collateral arteries in pulmonary atresia with ventricular septal defect.

INTRODUCTION: Pulmonary atresia with the ventricular septal defect is a rare congenital heart defect with high anatomic variability. The most important management question relates to the sources of pulmonary blood flow. The ability to differentiate between ductal dependence and major aortopulmonary collateral arteries is critical to achieving good outcomes and avoiding life-threatening hypoxia in the postneonatal period. Having accurate information about pulmonary arteries, major aortopulmonary collateral arteries, and sources of blood supply to each pulmonary segment is crucial for choosing the optimal surgical strategy. The purpose of this study is to compare computed tomography angiography (CTA) with cardiac catheterization for anatomic delineation of surgically relevant anatomy in pulmonary atresia with ventricular septal defect with major aortopulmonary collateral arteries. MATERIALS AND METHODS: Retrospective review of all children with pulmonary atresia with ventricular septal defect with major aortopulmonary collateral arteries cared for at a large tertiary children's hospital who underwent cardiac catheterization with angiography and CTA close to each other without interval therapy. All studies were performed between 2007 and 2011. RESULTS: There were 9 patients who met the inclusion criteria. Pulmonary artery anatomy (confluent vs. nonconfluent) was correctly identified in 9 patients by CTA and 8 patients by catheterization. There were no significant differences between CTA and catheterization in the identification of major aortopulmonary collateral arteries (mean = 3.4 collaterals/study via catheterization; mean = 3.1 collaterals/study via CTA; P = 0.67). CTA was superior to catheterization in the delineation of segmental pulmonary blood flow (P = 0.006). CONCLUSION: CTA and catheterization are equivalent in their ability to delineate pulmonary artery anatomy and major aortopulmonary collateral arteries.

Resource Allocation and Decision Making for Pediatric and Congenital Cardiac Catheterization During the Novel Coronavirus SARS-CoV-2 (COVID-19) Pandemic: A U.S. Multi-Institutional Perspective.

BACKGROUND: The novel coronavirus (COVID-19) pandemic has placed severe stress on healthcare systems around the world. There is limited information on current practices in pediatric cardiac catheterization laboratories in the United States (US). OBJECTIVES: To describe current practice patterns and make recommendations regarding potential resource allocation for congenital cardiac catheterization during the COVID-19 pandemic. METHODS: A web-based survey was distributed regarding case candidacy and catheterization laboratory preparedness. Centers were categorized based on the current degree of disease burden in that community (as of April 1, 2020). Data and consensus opinion were utilized to develop recommendations. RESULTS: Respondents belonged to 56 unique US centers, with 27 (48.2%) located in counties with a high number of COVID-19 cases. All centers have canceled elective procedures. There was relative uniformity (>88% agreement) among centers as to which procedures were considered elective. To date, only three centers have performed a catheterization on a confirmed COVID-19 positive patient. Centers located in areas with a higher number of COVID-9 cases have been more involved in a simulation of donning and doffing personal protective equipment (PPE) than low-prevalence centers (46.7% vs 10.3%, respectively; P<.001). Currently, only a small fraction of operators has been reassigned to provide clinical services outside their scope of practice. CONCLUSIONS: At this stage in the COVID-19 pandemic, pediatric/congenital catheterization laboratories have dramatically reduced case volumes. This document serves to define current patterns and provides guidance and recommendations on the preservation and repurposing of resources to help pediatric cardiac programs develop strategies for patient care during this unprecedented crisis.

Left Ventricular Strain Normalizes After Balloon Aortic Valvuloplasty in Infants with Congenital Aortic Stenosis.

Severe aortic stenosis (AS) causes left ventricular (LV) afterload and subendocardial ischemia. Despite this, most infants with AS have normal LV ejection fraction (EF). Strain analysis using two-dimensional speckle tracking echocardiography (2DSTE) may identify more sensitive markers of systolic dysfunction. We sought to show changes in LV strain after balloon aortic valvuloplasty (BAV) in infants with AS. Twenty-seven infants ≤ 1 year of age with AS who underwent BAV from 2007 to 2017 were included. Echocardiograms before/after BAV were retrospectively analyzed with 2DSTE. Median age was 29 days (interquartile range 3-52) and LV EF was 64 ± 10%. Global longitudinal strain (GLS) significantly improved post-BAV (- 17 ± 5 vs. - 20 ± 4%, p = 0.001) with no difference in global circumferential strain. Peak longitudinal strain was abnormal at the inferoseptal base and mid-ventricle (- 15 ± 6 and - 17 ± 5 = 7%, respectively) and significantly improved in the basal and mid-anterolateral segments (- 17 ± 5 vs. - 21 ± 5%, p < 0.01; - 17 ± 6% vs. - 20 ± 5%, p = 0.01, respectively). Five (20%) patients underwent reintervention, and had significantly higher peak-to-peak pre and post-BAV AS gradients (86 ± 14 vs. 61 ± 20 mmHg, p = 0.02; 33 ± 17 vs. 21 ± 10 mmHg, p = 0.04, respectively). In conclusion, longitudinal strain is abnormal in infants with AS and improves to previously published normal values after BAV.

Safety and Outcomes of Transcatheter Closure of Patent Ductus Arteriosus in Children With Pulmonary Artery Hypertension.

To investigate whether transcatheter device closure of patent ductus arteriosus (PDA) is safe in children with pulmonary artery hypertension, we retrospectively analyzed our experience with 33 patients who underwent the procedure from January 2000 through August 2015. Pulmonary artery hypertension was defined as a pulmonary vascular resistance index (PVRI) >3 WU · m2. All 33 children (median age, 14.5 mo; median weight, 8.1 kg) underwent successful closure device implantation and were followed up for a median of 17.2 months (interquartile range [IQR], 1.0-63.4 mo). During catheterization, the median PVRI was 4.1 WU · m2 (IQR, 3.6-5.3 WU · m2), and the median mean pulmonary artery pressure was 38.0 mmHg (IQR, 25.5-46.0 mmHg). Premature birth was associated with pulmonary vasodilator therapy at time of PDA closure ( P=0.001) but not with baseline PVRI (P=0.986). Three patients (9.1%) had device-related complications (one immediate embolization and 2 malpositions). Two of these complications involved embolization coils. Baseline pulmonary vasodilator therapy before closure was significantly associated with intensive care unit admission after closure (10/12 [83.3%] with baseline therapy vs 3/21 [14.3%] without; P <0.001). Of 11 patients receiving pulmonary vasodilators before closure and having a device in place long-term, 8 (72.7%) were weaned after closure (median, 24.0 mo [IQR, 11.0-25.0 mo]). We conclude that transcatheter PDA closure can be performed safely in many children with pulmonary artery hypertension and improve symptoms, particularly in patients born prematurely. Risk factors for adverse outcomes are multifactorial, including coil use and disease severity. Multicenter studies in larger patient populations are warranted.

Fetal aortic valvuloplasty to prevent progression to hypoplastic left heart syndrome in utero.

Advances in fetal echocardiography have allowed for the prenatal diagnosis of congenital heart disease and an understanding of its natural history in utero. This insight has led to the development of fetal cardiac intervention (FCI) for select defects to prevent significant morbidity or mortality postnatally. Fetal aortic valvuloplasty (FAV) may be performed to prevent progression to hypoplastic left heart syndrome, a severe form of congenital heart disease, in utero. The current review focuses on this type of FCI and discusses the history of FAV, the rationale for intervention, candidate selection, procedural technique, and outcomes to date. Finally, the importance of building a multidisciplinary team to perform FCI is addressed.

Intentional Fracture of Bioprosthetic Valve Frames in Patients Undergoing Valve-in-Valve Transcatheter Pulmonary Valve Replacement.

BACKGROUND: Percutaneous transcatheter pulmonary valve replacement (TPVR) has good clinical and hemodynamic outcomes in treating dysfunctional bioprosthetic valves (BPV) in the pulmonary position. Valve-in-valve therapy can further decrease the inner diameter (ID), potentially resulting in patient-prosthesis mismatch in patients with smaller BPVs. METHODS AND RESULTS: To evaluate feasibility and outcomes of intentional BPV fracture to enlarge the pulmonary valve orifice with TPVR, 37 patients from 13 centers who underwent TPVR with intended BPV fracture were evaluated. A control cohort (n=70) who underwent valve-in-valve TPVR without attempted fracture was evaluated. BPV was successfully fractured in 28 patients and stretched in 5 while fracture was unsuccessful in 4. A Melody valve was implanted in 25 patients with fractured/stretched frame and a Sapien (XT 3) valve in 8. Among patients whose BPV was fractured/stretched, the final ID was a median of 2 mm larger (0-6.5 mm) than the valve's true ID. The narrowest diameter after TPVR in controls was a median of 2 mm smaller ( P<0.001) than true ID. Right ventricular outflow tract gradient decreased from median 40 to 8 mm Hg in the fracture group. Cases with fracture/stretching were matched 1:1 (weight, true ID) to controls. Post-TPVR peak gradient was lower but not significant (8.3±5.2 versus 11.8±9.2 mm Hg; P=0.070). There were no fracture-related adverse events. CONCLUSIONS: Preliminary experience shows intentional fracture of BPV frame can be useful for achieving larger ID and better hemodynamics after valve-in-valve TPVR.

Transcatheter stenting of superior vena cava obstruction after pediatric heart transplantation: A single-center experience assessing risk factors and outcomes.

Transcatheter stent implantation for SVC obstruction following OHT has been well described, particularly in pediatric patients. This study describes a large single-center pediatric heart transplant experience that investigates the risk factors for SVC stenosis requiring stent implantation and its associated outcomes. All pediatric OHTs between January 1, 2000, and December 12, 2016, were examined for risk factors. Twelve of 349 (3.4%) OHTs required SVC stent implantation. Patients who required stents were younger (2.5 years vs 10.0 years, P = 0.0097), weighed less (8.6 kg vs 26.0 kg, P = 0.0024), and were more likely to have had CHD (83% vs 32%, P = 0.001) or previous SCPA (58% vs 18%, P = 0.002). Bicaval anastomosis was not associated with subsequent SVC stent implantation. Symptoms included SVC syndrome and chylous effusions. All 12 patients had evidence of significant SVC obstruction by both echocardiographic Doppler interrogation and transcatheter angiography. There were no acute procedural complications; however, reinterventions were common (four of 12 patients) and occurred at a mean of 5.7 ± 3.6 months poststent implantation. In conclusion, transcatheter SVC stent implantation is safe and effective after OHT. There were significant associations between SVC stent implantation and younger age, smaller weight, CHD, and history of SCPA, but not with bicaval anastomosis or donor-recipient weight ratio.

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.

Drug-Coated Balloon Angioplasty: A Novel Treatment for Pulmonary Artery In-Stent Stenosis in a Patient with Williams Syndrome.

A 20-month-old boy with Williams syndrome had undergone multiple surgical and catheter-based interventions for resistant peripheral pulmonary arterial stenoses with eventual bilateral stent placement and conventional balloon angioplasty. He persistently developed suprasystemic right ventricular (RV) pressure. Angioplasty with a drug-coated balloon (DCB) was performed for in-stent restenosis and to remodel his distal pulmonary vessels bilaterally. This resulted in immediate improvement in the in-stent stenosis and resultant decrease in RV pressure. Follow-up catheterization two months later continued to show long-lasting improvement in the in-stent stenosis. We hypothesize that the anti-proliferative effects of DCBs may be of benefit in the arteriopathy associated with Williams syndrome. We report this as a novel use of a DCB in the pulmonary arterial circulation in a patient with Williams syndrome.

Expansion Characteristics of Stents Used in Congenital Heart Disease: Serial Dilation Offers Improved Expansion Potential Compared to Direct Dilation: Results from a Pediatric Interventional Cardiology Early Career Society (PICES) Investigation.

OBJECTIVE: Intravascular stents are now routinely used to treat young patients with vascular stenoses. Future stent redilations are often necessary to account for somatic growth. The purpose of this study was to compile a database of characteristics for stents commonly used in the treatment of congenital heart disease patients, and compare serial dilation to direct dilation to the maximal diameter. DESIGN: A standardized bench testing protocol was established and utilized in the assessment of all stents. Ultra high pressure balloons were used to serially dilate each stent by set increments until the stent reached at least 24 mm in diameter, developed a napkin-ring configuration, or fractured. Length and diameter of each stent were measured at baseline and following each stage of dilation. Maximal stent diameters, foreshortening properties, and ability to fracture were reported. Stents were then tested for direct dilation from the primary diameter to the maximal diameter, and the same data was obtained. RESULTS: A total of 127 stents were bench-tested, 80 of which were serially dilated and 47 directly dilated. Most premounted stents could be serially dilated to approximately twice their stated nominal diameter. All tested unmounted stents could be serially dilated to ≥20 mm. Foreshortening occurred at larger diameters, but varied significantly among different stent types. Serial dilation offered more consistent results with significantly less foreshortening and more symmetric expansion when compared with direct dilation. Most premounted stents could be fractured when serially dilated. CONCLUSIONS: All tested vascular stents can be dilated beyond their nominal implantation diameter. Serial dilation offers a much more reliable response with uniform expansion, less foreshortening, greater maximal diameter, and improved intentional fracture potential, as compared to direct dilation from the nominal to maximal diameter. In vivo studies are necessary to corroborate these findings in the congenital heart disease population.