Is there a role for endovascular stent implantation in the management of postoperative right ventricular outflow tract obstruction in the era of transcatheter valve implantation?

BACKGROUND: The optimal management pathway for the dysfunctional right ventricular outflow tract (RVOT) is uncertain. We evaluated the long-term outcomes and clinical impact of stent implantation for obstructed RVOTs in an era of rapidly progressing transcatheter pulmonary valve technology. METHODS: Retrospective review of 151 children with a biventricular repair who underwent stenting of obstructed RVOT between 1991 and 2017. RESULTS: RVOT stenting resulted in significant changes in peak right ventricle (RV)-to-pulmonary artery (PA) gradient (39.4 ± 17.1-14.9 ± 8.3; p < 0.001) and RV-to-aortic pressure ratio (0.78 ± 0.22-0.49 ± 0.13; p < 0.001). Subsequent percutaneous reinterventions in 51 children to palliate recurrent stenosis were similarly effective. Ninety-nine (66%) children reached the primary outcome of subsequent pulmonary valve replacement (PVR). Freedom from PVR from the time of stent implantation was 91%, 51%, and 23% at 1, 5, and 10 years, respectively. Small balloon diameters for stent deployment were associated with shorter freedom from PVR. When additional children without stent palliation (with RV-to-PA conduits) were added to the stent cohort (total 506 children), the multistate analysis showed the longest freedom from PVR in those with stent palliation and subsequent catheter reintervention. Pulmonary regurgitation was well-tolerated clinically. Indexed RV dimensions and function estimated by echocardiography remained stable at last follow up or before primary outcome. CONCLUSION: Prolongation of conduit longevity with stent implant remains an important strategy to allow for somatic growth to optimize the risk-benefit profile for subsequent surgical or transcatheter pulmonary valve replacement performed at an older age.

Impacts of early cardiac catheterization for children with congenital heart disease supported by extracorporeal membrane oxygenation.

BACKGROUND: Cardiac catheterization is often required for patients on extracorporeal membranous oxygenation (ECMO) support, though its efficacy remains unclear. This study aimed to assess the impact of catheterization on successful ECMO weaning. METHODS: This is a single-center retrospective study from 2000 to 2014. Patients with congenital heart disease who underwent cardiac catheterization while on cardiac ECMO support were included. Logistic regression analysis and Kaplan-Meier survival analysis with log-rank test were performed to determine predictors for successful weaning and patient outcome. RESULTS: Forty-nine catheterizations in 47 patients with the median age of 65 days (range: 1 day-12 years) and the median body weight of 4.2 kg (range: 1.9-32.7 kg) were included. Median duration between ECMO cannulation and catheterization was 1 day (range: 0-11 days). Thirty-three patients (70%) succeeded in decannulation and 24 patients (51%) survived to hospital discharge. Absence of renal (P = 0.045) and respiratory complications (P = 0.031) were significant prognostic factors for successful weaning in multivariate analysis. Patients who received catheterization within 48 hr after ECMO cannulation demonstrated less respiratory complications (P = 0.006) and better survival at 30 days after ECMO initiation (P = 0.039) than those who underwent later catheterization. There was no mortality; however, nine major catheterization-related complications (18%) were detected. CONCLUSION: Catheterization for pediatric patients on ECMO support can be performed, although this group contained high risk of serious adverse events. The absence of ECMO complications is a predictor for successful weaning. An earlier catheterization appears to be associated with better short-term survival in this cohort. © 2016 Wiley Periodicals, Inc.

Clinical Impact of Stent Implantation for Coarctation of the Aorta with Associated Hypoplasia of the Transverse Aortic Arch.

The aim of this study was to explore the clinical impact of transverse aortic arch hypoplasia (TAH) after stent implementation for isthmal coarctation of the aorta (CoA). From a retrospective chart review, 51 children (median age 11.1 years) were identified who had TAH and a CoA stent implanted between 10/1995 and 4/2015. Arm-leg cuff blood pressure measurements, echocardiographic arch imaging, and 24-h ambulatory blood pressure monitoring, prior to and after stent implantation, were reviewed. At catheterization, peak systolic gradients across the CoA's were 25 mmHg before and 4 mmHg after stent implantation. At a median 37-month follow-up, echocardiographic imaging showed no significant catch-up growth in the transverse arch (median z-score; proximal and distal arch -1.54 and -1.99 vs. -1.78 and -1.63, p = 0.13 and 0.90). A trend to increasing systolic blood pressure (SBP) differentials between the right and left arms was noted (11 mmHg [prior to]; 16 mmHg [follow-up], p = 0.09). Age-adjusted percentiles for right arm SBP decreased from 99.7% prior to, and 87.6% in follow-up (p < 0.001). The median time to re-intervention was 5.6 years (95% CI [2.8, 7.8]) and the proportion of children using anti-hypertensive in follow-up was not significantly different before the implantation (38% [prior to]; 45% [follow-up]). Elevated right arm blood pressure persists after successful stent implantation in the setting of associated TAH and there appears to be no catch-up growth of the transverse arch with time. Medical management can be difficult and approaches to surgical arch augmentation or stent implantation should be considered to avoid unilateral arm hypertension.

Characteristics of secundum atrial septal defects not percutaneously closed.

OBJECTIVES: We sought to review our single center experience with secundum atrial septal defect (ASD) device closure, evaluating the incidence and morphological characteristics where percutaneous closure was thought inappropriate. MATERIAL AND METHODS: All children assessed as unsuitable for transcatheter device closure were reviewed. Data collected included: demographics, defect morphology by echocardiography or at cardiac catheterization and defect size focusing on the reasons for procedural deferral. RESULTS: Between January 2002 and December 2010, 639 children underwent closure of an isolated secundum ASD: 82 children (13%) where referred directly to surgery, 43 (6%) were thought unsuitable for device closure at the time of catheterization and underwent subsequent surgery and the remaining 514 (81%) underwent successful device closure including 2 on a second attempt. The reasons for pursuing a surgical closure (n = 124, mean age = 5.7 years; range: 0.6-17.4 years; defect diameter/body weight = 1.39) included: the need for a device thought too large for implantation versus the child's size (n = 51), defects with deficient rim(s) (n = 48), multiple defects (n = 7), defects sized >36 mm (n = 2), malposition (n = 2), ECG changes (n = 3), aneurysmal IAS (n = 2), sinus venosus (n = 2), or others (n = 7). CONCLUSION: The reasons for deferring transcatheter device closure of a secundum ASD are diverse, not only isolated rim deficiencies but the requirements of large implants, malposition, arrhythmias, and lack of hemodynamic need are influential components in clinical decision making.

Achievable radiation reduction during pediatric cardiac catheterization: How low can we go?

OBJECTIVES: To assess the effectiveness of radiation-reduction measures implemented during pediatric catheterization, and provide data on the radiation doses for common interventional and diagnostic procedures, indexed to body weight. BACKGROUND: Ionizing radiation exposure must be minimized to "as low as reasonably achievable," by instituting radiation-limiting techniques and knowledge of expected radiation exposure. METHODS: Radiation-reduction measures included pulsed-fluoroscopy at 7.5 pulses/second (0.032-0.045 µGy/pulse), an air-gap magnification technique for children<20 kg, operator awareness, and additional exposure reduction techniques through projection optimization. Radiation doses for procedures performed between 2007 through 2014 were retrospectively reviewed, including dose area product (DAP) and DAP/kg of body weight for 25 procedural types. Median doses were compared with those previously published from other large centers and multi-institutional databases and assessed for changes over time. RESULTS: Reviewed were 5,196 cases, which included 2,819 interventional, 710 endomyocardial biopsies and 1,667 diagnostic studies, documenting a significant difference in exposure between various procedures and body weights. The absolute exposure was significantly greater in larger children (e.g., for ductal closure median DAP/kg: 17 µGy*m2/kg 10-20 kg children vs. 37 µGy*m2 /kg for those>30 kg, P<0.001). Dose exposure using radiation-reduction techniques were the lowest reported in the literature for all procedure types compared (e.g. median DAP for pulmonary valvuloplasty 163 µGy*m2 vs. 405 to 1,230 µGy*m2 reported by 3 large centers). Reduction of fluoroscopy acquisition to 7.5 pulses/second nearly halved radiation exposure (P<0.001). CONCLUSIONS: Implementing a radiation dose reduction and awareness program can lead to documented reduction in exposure, across a variety of procedures performed by multiple operators.

Three-dimensional rotational angiography in the assessment of vascular and airway compression in children after a cavopulmonary anastomosis.

The aim of the study was to examine the role of three-dimensional rotational angiography (3DRA) in assessing vascular and airway narrowing in children with a bidirectional cavopulmonary anastomosis (BCPA). The course of children with single ventricle physiology is often complicated by left pulmonary artery (LPA) and/or bronchial stenosis and may be related to aortic compression. 3DRA may be useful in evaluating this complex anatomy and possible mechanisms for the observed obstruction. Clinical data and imaging (2D angiography and 3DRA) of children with a BCPA were reviewed retrospectively. Measurements were taken at similar locations along the pulmonary arteries in both modalities and in the airways on 3DRA. Twenty-five children with a previous BCPA were assessed at mean age of 3.1 ± 2.0 years and weight of 13.6 ± 3.6 kg. Excellent correlation was found between 3DRA and 2D angiographic LPA measurements (r = 0.89, p < 0.0001). Twelve children had qualitative LPA stenosis on 3DRA, with a stenotic dimension of 6.6 ± 2.2 mm on 2D angiography and 6.8 ± 1.9 mm on 3DRA (r = 0.94, p < 0.0001). Ten cases with LPA stenosis also had bronchial stenosis (83 %). Qualitative airway assessment correlated with quantitative bronchial dimensions from 3DRA-derived tomographic images: Bronchial stenosis measured 4.4 ± 1.6 versus 5.9 ± 1.1 mm in those with a normal appearing bronchus (p = 0.009). Hybrid patients (initial palliation with bilateral pulmonary artery banding and arterial ductal stenting, n = 5) and all patients with a Damus-Kaye-Stansel (DKS) anastomosis (n = 9) were more likely to have LPA and left bronchial stenosis (OR 7.7, p = 0.04). 3DRA is a useful and accurate tool in assessment of LPA and airway narrowing after BCPA. Hybrid and DKS patients are more prone to LPA and bronchial stenosis, and 3DRA can provide insight into the mechanism.

Surgical palliation strategy does not affect interstage ventricular dysfunction or atrioventricular valve regurgitation in children with hypoplastic left heart syndrome and variants.

BACKGROUND: All 3 palliation strategies, Norwood, Sano, and Hybrid, currently used for hypoplastic left heart syndrome pose a risk of myocardial injury at different times and through different mechanisms. We sought to compare these strategies to understand longitudinal differences in interstage ventricular dysfunction and their subsequent impact on transplant-free survival and atrioventricular valve regurgitation (AVVR) as well as the relationship between adverse events and ventricular function. METHODS AND RESULTS: Serial echocardiographic reports and clinical data were reviewed for 138 children with hypoplastic left heart syndrome who underwent stage I surgical palliation (Sano: 11; Norwood: 73; Hybrid: 54) between 2004 and 2011. Stage II palliation was achieved in 92 (67%) patients (Sano: 7; Norwood: 51; Hybrid: 34). Interstage transplant-free survival, ventricular dysfunction, and AVVR were equivalent among palliation strategies. Patients with preserved ventricular function had a higher rate of transplant-free survival and freedom from AVVR, regardless of palliation strategy. Patients who had cardiac arrest, cardiopulmonary resuscitation, or extracorporeal membrane oxygenation (adverse events) experienced more transient and persistent ventricular dysfunction compared to those without adverse events. Surgical palliation strategies were not identified as risk factors for ventricular dysfunction or AVVR. CONCLUSIONS: Surgical palliation strategy does not affect mortality, interstage ventricular function, or interstage AVVR in children with hypoplastic left heart syndrome. Therefore, the different timing and mechanisms of myocardial injury among palliation strategies do not affect outcomes. Ventricular dysfunction adversely affects transplant-free survival and atrioventricular valve function. Adverse events are associated with the development of ventricular dysfunction. To improve outcomes, interstage treatment should focus on the preservation of ventricular function.

Intervention for recoarctation in the single ventricle reconstruction trial: incidence, risk, and outcomes.

BACKGROUND: Recoarctation after the Norwood procedure increases risk for mortality. The Single Ventricle Reconstruction (SVR) trial randomized subjects with a single right ventricle undergoing a Norwood procedure to a modified Blalock-Taussig shunt or a right ventricle-pulmonary artery shunt. We sought to determine the incidence of recoarctation, risk factors, and outcomes in the SVR trial. METHODS AND RESULTS: Recoarctation was defined by intervention, either catheter based or surgical. Univariate analysis and multivariable Cox proportional hazard models were performed with adjustment for center. Of the 549 SVR subjects, 97 (18%) underwent 131 interventions (92 balloon aortoplasty, 39 surgical) for recoarctation at a median age of 4.9 months (range, 1.1-10.5 months). Intervention typically occurred at pre-stage II catheterization (n=71, 54%) or at stage II surgery (n=38, 29%). In multivariable analysis, recoarctation was associated with the shunt type in place at the end of the Norwood procedure (hazard ratio, 2.0 for right ventricle-pulmonary artery shunt versus modified Blalock-Taussig shunt; P=0.02), and Norwood discharge peak echo-Doppler arch gradient (hazard ratio, 1.07 per 1 mm Hg; P<0.01). Subjects with recoarctation demonstrated comorbidities at pre-stage II evaluation, including higher pulmonary arterial pressures (15.4±3.0 versus 14.5±3.5 mm Hg; P=0.05), higher pulmonary vascular resistance (2.6±1.6 versus 2.0±1.0 Wood units·m(2); P=0.04), and increased echocardiographic volumes (end-diastolic volume, 126±39 versus 112±33 mL/BSA(1.3), where BSA is body surface area; P=0.02). There was no difference in 12-month postrandomization transplantation-free survival between those with and without recoarctation (P=0.14). CONCLUSIONS: Recoarctation is common after Norwood and contributes to pre-stage II comorbidities. Although with intervention there is no associated increase in 1-year transplantation/mortality, further evaluation is warranted to evaluate the effects of associated morbidities.

Infolding of covered stents used for aortic coarctation: report of two cases.

Covered stents have been used for the treatment of aortic coarctation to protect the arterial wall during dilation. Early results have shown them to be safe and effective. We report two cases of infolding of the proximal edge of a covered aortic coarctation stent. Management required implantation of a second stent. Poor stent apposition to the vessel wall and/or recoil may allow conditions for these events to occur.

Direct measurement of aortic regurgitation with phase-contrast magnetic resonance is inaccurate: proposal of an alternative method of quantification.

BACKGROUND: Phase-contrast magnetic resonance (MR) has been widely used for quantification of aortic regurgitation. However there is significant practice variability regarding where and how the blood flow data are acquired. OBJECTIVE: To compare the accuracy of flow quantification of aortic regurgitation at three levels: the ascending aorta at the level of the right pulmonary artery (level 1), the aortic valve hinge points at end-diastole (level 2) and the aortic valve hinge points at end-systole (level 3). MATERIALS AND METHODS: We performed cardiovascular MR in 43 children with aortic regurgitation. By using phase-contrast MR, we measured the systolic forward, diastolic retrograde and net forward flow volume indices at three levels. At each level, the following comparisons were made: (1) systolic forward flow volume index (FFVI) versus left ventricular cardiac index (LVCI) measured by cine ventricular volumetry; (2) retrograde flow volume index (RFVI) versus estimated aortic regurgitation volume index (which equals LVCI minus pulmonary blood flow index [QPI]); (3) net forward flow volume index (NFVI) versus pulmonary blood flow index. RESULTS: The forward flow volume index, retrograde flow volume index and net forward flow volume index measured at each of the three levels were significantly different except for the retrograde flow volume index measured at levels 1 and 3. There were good correlations between the forward flow volume index and the left ventricular cardiac index at all three levels, with measurement at level 2 showing the best correlation. Compared to the forward flow volume indices, the retrograde flow volume index had a lower correlation with the estimated aortic regurgitation volume indices and had widely dispersed data with larger prediction intervals. CONCLUSION: Large variations in systolic forward, diastolic retrograde and net forward flow volumes were observed at different levels of the aortic valve and ascending aorta. Direct measurement of aortic regurgitation volume and fraction is inaccurate and should be abandoned. Instead, calculation of the aortic regurgitation volume from more reliable data is advised. We recommend subtracting pulmonary blood flow from systolic forward flow measured at the aortic valve hinge points at end-diastole as a more accurate and consistent method for calculating the volume of aortic regurgitation.

Hybrid versus Norwood strategies for single-ventricle palliation.

BACKGROUND: Hybrid and Norwood strategies differ substantially in terms of stage II palliative procedures. We sought to compare these strategies with an emphasis on survival and reintervention after stage II and subsequent Fontan completion. METHODS AND RESULTS: Of 110 neonates with functionally single-ventricle physiology who underwent stage I palliation between 2004 and 2010, 75 (69%) infants (Norwood, n=43; hybrid, n=32) who subsequently underwent stage II palliation were studied. Survival and reintervention rates after stage II palliation, anatomic and physiologic variables at pre-Fontan assessment, and Fontan outcomes were compared between the groups. Predictors for reintervention were analyzed. Freedom from death/transplant after stage II palliation was equivalent between the groups (Norwood, 80.4% versus hybrid, 85.6% at 3 years, P=0.66). Hybrid patients had a higher pulmonary artery (PA) reintervention rate (P=0.003) and lower Nakata index at pre-Fontan evaluation (P=0.015). Aortic arch and atrioventricular valve reinterventions were not different between the groups. Ventricular end-diastolic pressure, mean PA pressure, and ventricular function were equivalent at pre-Fontan assessment. There were no deaths after Fontan completion in either group (Norwood, n=25, hybrid, n=14). CONCLUSIONS: Survival after stage II palliation and subsequent Fontan completion is equivalent between the groups. The hybrid group had a higher PA reintervention rate and smaller PA size. Both strategies achieved adequate physiology for Fontan completion. Evolution of the hybrid strategy requires refinement to provide optimal PA growth.

Experience with the Atrium Advanta covered stent for aortic obstruction.

INTRODUCTION: We sought to assess the efficacy, safety and clinical outcomes of the Advanta V12™ covered stent in management of coarctation of the aorta (CoA). MATERIALS AND METHODS: Stent functionality was assessed by review of angiographic imaging, clinical data at admission, discharge and at the last clinic visit, stent configuration on chest roentgenogram, radiation exposure, and complications. RESULTS: Between October 2009 and February 2012, 17 patients underwent stent implantation. There were 9-12, 2-14, and 6-16 mm diameter stents deployed. Balloon angioplasty after implantation was required in 2 patients. Mean percent recoil in the middle of the stent for the 12, 14, and 16 mm implants was 14%, 24%, and 24%, respectively. There was improvement in CoA diameter from 6.6 ± 3.2 to 11.5 ± 1.7 mm (P<0.0001) and a reduction in the peak pressure gradient from 23.1 ± 10.1 to 0.8 ± 3.3 mmHg (P<0.0001). No patient had a symptomatic complication. Left arm cuff blood pressure fell 24 hours after implantation and left arm to leg blood pressure gradient fell to <20 mmHg in all (P<0.0001). Follow-up was a median 242 days and at the last clinic visit there were no statistically different findings from discharge. Five children (33%) required antihypertensive medications but 3 were off medication at latest follow-up. Three patients (18%) required reintervention. CONCLUSION: The implantation of the Advanta™ V12 stent for the treatment of CoA is safe and effective in the early term. However, further study is required to determine longer-term stent efficacy.

The fellows stitch: large caliber venous hemostasis in pediatric practice.

OBJECTIVE: To analyze safety and efficiency of a subcutaneous figure of eight suture for hemostasis after large caliber venous sheath access in children. BACKGROUND: Vascular complications remain a significant cause of morbidity after pediatric cardiac catheterization. In an attempt to reduce such complications and yet improve lab efficiency and decrease length of stay, various techniques have been applied to improve time to hemostasis. METHODS: Prospectively recorded were vascular complications and hemostasis times in children where hemostasis was attempted using a figure of eight subcutaneous suture following large caliber venous cannulation. These were compared to a matched group achieving hemostasis using standard manual pressure techniques. Vascular ultrasound assessments were performed within 24 hr of hemostasis in both groups. RESULTS: Thirty-two subcutaneous sutures were placed in 26 children, mean weights 31.9 kg [median (range): 29.4 (8.4 to 96) kg], with a mean sheath French size of 9.2 [8; (6 to 22)], 11 >10 French, compared to 33 sheaths in 30 cases using manual compression, mean sheath French size 9.1 (9; (6 to 13), with 10 cases ≥10 French. The mean and median times to hemostasis were shorter in the suture group: 13.6 min (P < 0.05) and 10 min (P < 0.05), respectively. Vascular complication rate was also lower in the suture group (n = 0) compared with the control group (n = 2) but did not achieve statistical significance. CONCLUSIONS: A subcutaneous figure of eight suture hemostasis strategy can provide a safe and efficient method for large caliber venous hemostasis in a pediatric practice with improved hemostasis times and no additional morbidity.

Biventricular Repair in Borderline Left Hearts: Insights From Cardiac Magnetic Resonance Imaging.

Background: Cardiac magnetic resonance imaging (CMR) may augment 2-dimensional (2D) echocardiography in decision-making for biventricular repair in borderline hypoplastic left hearts. Objectives: This study evaluates: 1) the relationship between 2D echocardiography and CMR; 2) imaging variables affecting assignment to biventricular vs non-biventricular management; and 3) variables affecting transplant-free biventricular survival. Methods: We reviewed clinical, echocardiographic, and CMR data in 67 infants, including CMR-determined ascending aortic (AAo) flow and comparable left ventricular end-diastolic volume indexed (LVEDVi) by 2D-echocardiography and CMR. Results: Treatment assignment to biventricular repair was either direct (BV, n = 45) or with a bridging hybrid procedure (H1-BV, n = 12). Echocardiographic LVEDVi was <20 mL/m2 in 83% of biventricular repair infants and underestimated CMR-LVEDVi by 16.8 mL/m2. AAo flows had no/weak correlation with aortic and mitral valve z-scores or LVEDVi. AAo flows differed between BV, H1-BV, and single-ventricle groups (median): 2.1, 1.7, and 0.7 L/min/m2, respectively. Important variables for treatment assignment were presence of endocardial fibroelastosis, AAo flow, and mitral valve z-score. Biventricular repair was achieved in 54. The median follow-up was 8.0 (0.1-16.4) years. Transplant-free biventricular survival was 96%, 82%, and 77% at 1, 5, and 10 years, respectively. Patients without aortic coarctation repair were at higher risk of death, transplantation, or single-ventricle conversion (HR: 54.3; 95% CI: 6.3-47.1; P < 0.001) during follow-up. AAo flow had a smaller nonlinear effect with hazard ratio increasing at lower flows. Conclusions: Historical 2D echocardiographic criteria would have precluded many patients from successful biventricular repair. AAo flow, an integrative index of left heart performance, was important in assigning patients to a biventricular circulation and affected survival. Biventricular survival was strongly associated with the need for aortic coarctation repair.

Current-Era Outcomes of Balloon Aortic Valvotomy in Neonates and Infants.

Background: The optimal initial treatment pathway for aortic valve stenosis remains debated. Objectives: The objective of this study was to review current outcomes of balloon aortic valvotomy (BAV) in neonates and infants. Methods: Neonates and infants with a biventricular circulation treated with BAV between 2004 and 2019 were reviewed. Results: One hundred thirty-nine infants (48% neonates) with median (Q1, Q3) age of 33(7, 84) days and weight 4.0 (3.4, 5.1) kg were followed up for 7.1 (3.3, 11.0) years. BAV reduced peak-to-peak gradient from mean (SD) 52 (16) mmHg to 18 (12) mmHg; P < 0.001. Aortic regurgitation (AI) increased with time after BAV. Three children died during follow-up. Fifty-one reinterventions (26 BAV, 19 aortic valve replacements [AVRs], and 6 surgical valvotomies) were performed on 40 children. Freedom from AVR (95% CI) was 96% (93%-99%) at 1, 91% (86%-96%) at 5, and 86% (79%-93%) at 10 years. The predictors of AVR were a unicommissural valve (hazard ratio [HR] [95% CI]: 3.7 [1.4-9.6]; P = 0.007) and moderate to severe AI after index BAV (HR [95% CI]: 3.3 [1.1-9.7]; P = 0.029). Freedom from reintervention was 84% (78%-90%) at 1, 76% (69%-83%) at 5, and 69% (60-78%) at 10 years. Main predictors of reintervention were age below 1 month (HR [95% CI]: 2.1 [1.1-4.1]; P = 0.032) and postdilation peak-to-peak gradient (per 10-mmHg increase; HR [95% CI]: 1.36 [1.02-1.79]; P = 0.032). Conclusions: BAV is a safe and effective treatment for aortic valve stenosis in neonates and infants. Outcomes are competitive with contemporary published data on aortic valve repair in relation to mortality, gradient relief, long-term AVR, and reintervention rates. In the absence of significant AI, surgery can be reserved for those with gradients resistant to valve dilation.

Vascular hemostasis bandage compared to standard manual compression after cardiac catheterization in children.

BACKGROUND: Femoral venous and arterial approaches are the commonly used to obtain vascular access for pediatric cardiac catheterization. Hemostasis after catheter removal is usually obtained by manual compression. However, this technique is time consuming and at times painful. Although several closure devices are available for adults, they are not widely applicable in children. OBJECTIVES: To evaluate the safety and efficacy of a microporous polysaccharide hemospheres hemostasis (MPH) bandage compared to manual compression. METHODS: Prospective randomized study, involving 112 children after cardiac catheterization. One group received the MPH bandage, another manual compression. Compression time was predetermined by the size of sheath plus one minute. Success was defined as no bleeding or hematoma formation. If bleeding continued, compression was continued as needed and time to hemostasis recorded. Informed consent was obtained prior to randomization. Group comparisons were performed with a Student's t, Pearson's Chi Square, and Fisher's exact test as appropriate. RESULTS: Fewer children required a compression time of >15 min (P = 0.006) and more had a shorter time to hemostasis (P = 0.003) in the MPH group for venous access control. Time to hemostasis was also shorter in the MPH (P = 0.048) in arterial access cases, but the number of children requiring a compression time >15 min was the same. Complications including hematoma formation in each group were similar. CONCLUSIONS: The MPH bandage allows a shorter time to achieve hemostasis compared to manual compression. This improves turnaround time and laboratory efficiency.

Percutaneous pulmonary valve implantation within bioprosthetic valves.

AIMS: Replacement of bioprosthetic valves in the right ventricular (RV) outflow tract (RVOT) is inevitable due to acquired valvar dysfunction. Percutaneous pulmonary valve implantation (PPVI) may result in acceptable clinical improvement avoiding surgical reintervention. To report outcomes of PPVI in dysfunctional surgically implanted bioprosthetic valves. METHODS AND RESULTS: All children undergoing PPVI into a bioprosthetic pulmonary valve between October 2005 and February 2008 were reviewed. Acute haemodynamic changes were compared and an analysis of variance applied to assess changes in ventricular geometry and pressure over time. Fourteen children (seven males), median weight 57.8 kg and 14.7 years of age were identified, with an echocardiographic RVOT gradient of 59.6 +/- 26.8 mmHg and a pulmonary regurgitation (PR) grade of 3.6 +/- 0.8 (out of 4). Implantation was successful in all. Twenty-four hours after implantation, there was a significant improvement in RV pressure (RVP) (from 82.2 +/- 15.6 to 59.4 +/- 9.9 mmHg, P < 0.001) and degree of PR to 0.6 +/- 0.9 (P < 0.001). Mean hospital stay was 2.0 +/- 0.4 days. Freedom from reintervention was 92 and 89% at 1 and 2 years, respectively. Follow-up echocardiography (mean 12.9 +/- 9.8 months) revealed a further reduction in RVP (P < 0.001) and RVOT gradients (P < 0.001) and an increase in left ventricular end-diastolic volume (P= 0.01) and aortic valve annulus diameters (P < 0.001). CONCLUSIONS: Percutaneous pulmonary valve implantation for RVOT dysfunction in a previously implanted prosthetic valve is feasible and safe. Short-term follow-up data are encouraging, yet longer-term information is required to determine if this form of palliation has a significant impact on management strategies.

Rapamycin-eluting stents in the arterial duct: experimental observations in the pig model.

BACKGROUND: Maintaining arterial duct patency by stent implantation may be advantageous in congenital heart disease management algorithms. Rapamycin, an immunosuppressant drug that demonstrates antiproliferative properties and inhibits smooth muscle cell migration, may deter the intimal hyperplasia that occurs during spontaneous closure and after-stent implantation of the arterial duct. METHODS AND RESULTS: Twenty-eight Yorkshire piglets (7 to 11 days old; weight, 2.2 to 4.9 kg) underwent stent implantation of the arterial duct (rapamycin-eluting (n=14) or bare metal (n=14) stents, 3.5-mm diameter) and were euthanized at 2, 4, and 6 weeks. Dissected arterial ducts were analyzed for lumen diameter, smooth muscle cell, and extracellular matrix components. Isolated arterial duct-derived smooth muscle cells were cultured in the presence or absence of rapamycin. Cellular proliferation rates were assessed by Ki-67 detection and [(3)H]-thymidine incorporation. No significant neointimal proliferation was present in either stent type at 2 weeks. At 4 weeks, the median luminal diameters of the bare metal stents were 87% (P=0.009), 54% (P=0.004), and 77% (P=0.004) that of the drug-eluting stents at the middle and aortic and pulmonary artery ends, respectively. At 6 weeks, the median luminal diameters of the bare metal stents were 0% (P=0.18), 5% (P=0.25), and 61% (P=0.13) that of the drug-eluting stents at the same respective levels. Complete histological occlusion was found in at least 1 level of the lumen in 9 pigs: 1 (17%) in the BMS group at 4 weeks, 5 (83%) in the BMS group at 6 weeks, and 3 (50%) in the DES group at 6 weeks. In vitro studies demonstrated 50%-lower proliferation rates in rapamycin-treated cultures of duct-derived smooth muscle cell cultures (P<0.001). CONCLUSIONS: Rapamycin has antiproliferative actions on the arterial duct. Drug-eluting stents may be a more efficient tool than current palliative options for maintaining patency in critically duct-dependent states, but there may be a finite time-related benefit.

A biodegradable device (BioSTAR) for atrial septal defect closure in children.

BACKGROUND: Percutaneous closure of atrial defects (ASD) has evolved as the treatment of choice for the majority of defects and patent oval foramens. The BioSTAR biodegradable implant avoids many issues associated with devices containing substantial amounts of metal. METHODS: Reviewed was a consecutive series of 10 ASD occlusions in a pediatric population with the BioSTAR biodegradable device. All implantations were performed by one operator. The inclusion criterion was a balloon stretched ASD diameter of < or =16 mm. Procedural data and acute and early-term closure rates were retrospectively matched to a cohort of children having defect closure using the Amplatzer Septal Occluder (ASO). RESULTS: Acute and 6 month follow up closure rates for the BioSTAR were 90% and 100% vs. 100% and 100% closure with the ASO implants. There was a statistically significant difference in the median procedure time (52 min: BioSTAR; 39.5 min: ASO device, P < 0.05), with fluoroscopy times slightly longer for the BioSTAR group (6.7 min vs. 6.1 min, P = ns). There were no significant complications in either group. CONCLUSIONS: The BioSTAR implant can achieve comparable closure rates to the ASO in small- to moderate-atrial septal defects with only a minimal skeleton of foreign material remaining after 6 months. Longer fluoroscopy and procedure times were a drawback; however, these should improve with familiarity with the implant and deployment system.

Balloon Angioplasty for Native Aortic Coarctation in 3- to 12-Month-Old Infants.

BACKGROUND: Balloon angioplasty for native coarctation of the aorta (CoA) is successful in children and adults but in neonates results in frequent restenosis. The efficacy of balloon angioplasty for native CoA during infancy beyond the neonatal period was examined in infants aged 3 to 12 months of age. METHODS: A retrospective review of 68 infants who underwent balloon angioplasty for native CoA. 95% CI are in parentheses. RESULTS: Procedural age was (mean±SD) 6±3.4 months and weight was 7±1.8 kg. Balloon angioplasty produced a large decrease in both the noninvasive arm-to-leg blood pressure gradient (41.2±18.7 to 5.6±9.6 mm Hg) and the invasive peak systolic pressure gradient (34±12 to 11±9 mm Hg). Balloon angioplasty increased the CoA diameter from 2.7±1 mm to 4.6±1.2 mm. One patient was lost to follow-up. A catheter reintervention was required in 11.8% and surgery in 10.3%. The hazard of reintervention was highest early. Median freedom from reintervention was 89% (95% CI, 80%-96%) at 1 year, 83% (95% CI, 73%-92%) at 5 years, and 81% (95% CI, 69%-90%) at 10 years. Femoral artery thrombosis was documented in 6 (9%) infants without any long-term consequence. One patient developed a small aortic aneurysm late and has not required treatment. A robust estimate of the frequency of aortic aneurysms remains to be determined as the majority of subjects have not had cross-sectional imaging. CONCLUSIONS: Balloon angioplasty of native CoA is effective and safe in infants aged 3 to 12 months with outcomes comparable to those in older children and adults. Catheter reinterventions can avoid the need for surgery in most patients.