Tissue expander-stimulated lengthening of arteries for the treatment of midaortic syndrome in children.

BACKGROUND: Midaortic syndrome (MAS) is a rare condition characterized by stenosis of the abdominal aorta. Patients with disease refractory to medical management will usually require either endovascular therapy or surgery with use of prosthetic graft material for bypass or patch angioplasty. We report our early experience with a novel approach using a tissue expander (TE) to lengthen the normal native arteries in children with MAS, allowing primary aortic repair without the need for prosthetic graft material. METHODS: We conducted a retrospective review of patients with MAS undergoing the TE-stimulated lengthening of arteries (TESLA) procedure at our institution from 2010 to 2014. Data are presented as mean (range). RESULTS: Five patients aged 4.8 years (3-8 years) underwent the TESLA procedure. Stages of this procedure include the following: stage I, insertion of retroaortic TE; stage II, serial TE injections; and stage III, final repair with excision of aortic stenosis and primary end-to-end aortic anastomosis. Stage II was completed in 4 months (1-9 months) with 12 (7-20) TE injections. Goal lengthening was achieved in all patients. Stage III could not be completed in one patient because of extreme aortic inflammation, which precluded safe excision of the aortic stenosis and required use of a prosthetic bypass graft. The other four patients completed stage III with two (one to three) additional vessels also requiring reconstruction (renal or mesenteric arteries). At 3.2 years (1-6 years) of follow-up, all patients are doing well. CONCLUSIONS: The TESLA procedure allows surgical correction of MAS without the need for prosthetic grafts in young children who are still growing.

Transcatheter Intervention of Coronary Obstructions in Infants, Children, and Young Adults.

This study assesses the characteristics of coronary obstructions that underwent transcatheter intervention in a pediatric catheterization laboratory, the procedural details, and patient outcomes. Acute cardiac failure due to coronary obstructions in children is rare. The role of catheter based intervention is largely unreported. Single center retrospective review between January 2000 and December 2016. Thirty-three patients (median age 2y/o [0-38], weighing 9.6 kg [2.2-91]) underwent 39 transcatheter interventions on 39 lesions, mainly left main coronary (16/39; 39%) and right coronary (9/39; 23%) arteries. Most patients had congenital heart disease (29/33; 88%). Cath indications included ventricular dysfunction (17), cardiac arrest (7), failure to wean from cardiopulmonary bypass (5), and other (4). Almost half (18/39; 46%) were performed on ECMO support. Obstructions were post-surgical (16; 4 with coronary manipulation), thrombotic (13; 5 < 30 days from cardiac surgery), and miscellaneous lesions (10). Interventions included 25 bare metal stents implanted in 22 lesions in 17 patients (mainly post-surgical lesions; 3 at Damus-Kaye-Stansel anastomosis), nine balloon angioplasty only, four lytic therapy ± mechanical disruption of thrombus, and four technical failures. There were no procedure-related deaths. Most patients survived to discharge or transplant (24/33; 73%). Six patients who received stents had follow-up catheterization (median 15.5 months [1-106]); all were without restenosis. Most coronary obstructions intervened upon in a pediatric cath lab were on young, critically ill patients with congenital heart disease secondary to surgical manipulation/injury or thrombosis. Transcatheter intervention should be considered a potential treatment strategy in this population.

Transcatheter Pulmonary Valve Replacement and Acute Increase in Diastolic Pressure are Associated with Increases in Both Systolic and Diastolic Pulmonary Artery Dimensions.

Stable positioning of a transcatheter pulmonary valve (TPV) in native outflow tracts depends on a clear understanding of underlying anatomy and outflow tract dimensions. We hypothesized that restoration of pulmonary competence may acutely alter these dimensions. A retrospective single-center review of consecutive patients after TPV placement from 2007 to 2014 was performed. Patients with less than moderate pulmonary regurgitation were excluded. We reviewed acute catheterization data on 46 patients, most with tetralogy of Fallot (70%). Baseline and post-implant (7.5 ± 3 min post-deployment) measurements of central pulmonary arteries (PAs) were determined angiographically. The right PA diameter increased (20 ± 4-24 ± 6 mm systole*, 16 ± 4-21 ± 6 mm diastole*), as did the left PA (20 ± 6-24 ± 8 mm systole*, 16 ± 5-21 ± 7 mm diastole*). PA pressures increased from averages of 29.3/10.6 (17) to 29.8/15.1 (21) mmHg. We noted that pre-implant systolic PA diameter correlated with diastolic PA diameter post-implant (r = 0.9). On follow-up catheterization in seven patients [median 3 years; (1-8)], combined central PA diameter decreased an average of 20% (systole: 20% ± 12, diastole: 18% ± 11) as compared to post-implant measurements. Acute pulmonary valve competence in patients with at least moderate pulmonary regurgitation results in an immediate increase in PA diameter (20% systole and 30% diastole). The cause of this diameter change is unclear. This acute change may have implications for device and patient selection (*p < 0.001).

Systemic rapamycin to prevent in-stent stenosis in peripheral pulmonary arterial disease: early clinical experience.

OBJECTIVES: We have taken a novel approach using oral rapamycin - sirolimus - as a medical adjunct to percutaneous therapy in patients with in-stent stenosis and high risk of right ventricular failure. BACKGROUND: Peripheral pulmonary artery stenosis can result in right ventricular hypertension, dysfunction, and death. Percutaneous pulmonary artery angioplasty and stent placement acutely relieve obstructions, but patients frequently require re-interventions due to re-stenosis. In patients with tetralogy of Fallot or arteriopathy, the problem of in-stent stenosis contributes to the rapidly recurrent disease. METHODS: Rapamycin was administered to 10 patients (1.5-18 years) with peripheral pulmonary stenosis and in-stent stenosis and either right ventricular hypertension, pulmonary blood flow maldistribution, or segmental pulmonary hypertension. Treatment was initiated around the time of catheterisation and continued for 1-3 months. Potential side-effects were monitored by clinical review and blood tests. RESULTS: Target serum rapamycin level (6-10 ng/ml) was accomplished in all patients; eight of the nine patients who returned for clinically indicated catheterisations demonstrated reduction in in-stent stenosis, and eight of the 10 patients experienced no significant side-effects. Among all, one patient developed diarrhoea requiring drug discontinuation, and one patient experienced gastrointestinal bleeding while on therapy that was likely due to an indwelling feeding tube and this patient tolerated rapamycin well following tube removal. CONCLUSIONS: Our initial clinical experience supports that patients with peripheral pulmonary artery stenosis can be safely treated with rapamycin. Systemic rapamycin may provide a novel medical approach to reduce in-stent stenosis.

A Pediatric Cardiology Fellowship Boot Camp improves trainee confidence.

Introduction New paediatric cardiology trainees are required to rapidly assimilate knowledge and gain clinical skills to which they have limited or no exposure during residency. The Pediatric Cardiology Fellowship Boot Camp (PCBC) at Boston Children's Hospital was designed to provide incoming fellows with an intensive exposure to congenital cardiac pathology and a broad overview of major areas of paediatric cardiology practice. METHODS: The PCBC curriculum was designed by core faculty in cardiac pathology, echocardiography, electrophysiology, interventional cardiology, exercise physiology, and cardiac intensive care. Individual faculty contributed learning objectives, which were refined by fellowship directors and used to build a programme of didactics, hands-on/simulation-based activities, and self-guided learning opportunities. RESULTS: A total of 16 incoming fellows participated in the 4-week boot camp, with no concurrent clinical responsibilities, over 2 years. On the basis of pre- and post-PCBC surveys, 80% of trainees strongly agreed that they felt more prepared for clinical responsibilities, and a similar percentage felt that PCBC should be offered to future incoming fellows. Fellows showed significant increase in their confidence in all specific knowledge and skills related to the learning objectives. Fellows rated hands-on learning experiences and simulation-based exercises most highly. CONCLUSIONS: We describe a novel 4-week-long boot camp designed to expose incoming paediatric cardiology fellows to the broad spectrum of knowledge and skills required for the practice of paediatric cardiology. The experience increased trainee confidence and sense of preparedness to begin fellowship-related responsibilities. Given that highly interactive activities were rated most highly, boot camps in paediatric cardiology should strongly emphasise these elements.

Fetal aortic valvuloplasty for evolving hypoplastic left heart syndrome: postnatal outcomes of the first 100 patients.

BACKGROUND: Fetal aortic valvuloplasty can be performed for severe midgestation aortic stenosis in an attempt to prevent progression to hypoplastic left heart syndrome (HLHS). A subset of patients has achieved a biventricular (BV) circulation after fetal aortic valvuloplasty. The postnatal outcomes and survival of the BV patients, in comparison with those managed as HLHS, have not been reported. METHODS AND RESULTS: We included 100 patients who underwent fetal aortic valvuloplasty for severe midgestation aortic stenosis with evolving HLHS from March 2000 to January 2013. Patients were categorized based on postnatal management as BV or HLHS. Clinical records were reviewed. Eighty-eight fetuses were live-born, and 38 had a BV circulation (31 from birth, 7 converted after initial univentricular palliation). Left-sided structures, namely aortic and mitral valve sizes and left ventricular volume, were significantly larger in the BV group at the time of birth (P<0.01). After a median follow-up of 5.4 years, freedom from cardiac death among all BV patients was 96±4% at 5 years and 84±12% at 10 years, which was better than HLHS patients (log-rank P=0.04). There was no cardiac mortality in patients with a BV circulation from birth. All but 1 of the BV patients required postnatal intervention; 42% underwent aortic or mitral valve replacement. On the most recent echocardiogram, the median left ventricular end-diastolic volume z score was +1.7 (range, -1.3 to +8.2), and 80% had normal ejection fraction. CONCLUSIONS: Short- and intermediate-term survival among patients who underwent fetal aortic valvuloplasty and achieved a BV circulation postnatally is encouraging. However, morbidity still exists, and ongoing assessment is warranted.

Percutaneous left atrial decompression in patients supported with extracorporeal membrane oxygenation for cardiac disease.

OBJECTIVES: Left atrial decompression using cardiac catheterization techniques has been described at centers with extracorporeal membrane oxygenation programs. Left atrial decompression can decrease cardiogenic edema, minimize ventricular distension, and allow myocardial recovery. We describe Boston Children's Hospital's experience with percutaneous left atrial decompression techniques, acute outcomes, and clinical impact of left atrial decompression in extracorporeal membrane oxygenation patients. SUBJECTS: Patients supported with extracorporeal membrane oxygenation undergoing percutaneous left atrial decompression were identified and assigned to two groups 1) myocarditis/suspected myocarditis or 2) nonmyocarditis cardiac disease. INTERVENTIONS: Three techniques including vent placement, static balloon dilation, and stent implantation were used. MEASUREMENTS AND MAIN RESULTS: Change in left atrial pressure and severity of pulmonary edema on chest radiography pre and post procedure, impact of timing and technique of left atrial decompression on resolution of left atrial hypertension, and extracorporeal membrane oxygenation survival were evaluated. Furthermore, we evaluated the presence of residual atrial septal defect during follow-up. Percutaneous left atrial decompression was performed in 44 of 419 extracorporeal membrane oxygenation cases (10.5%) and was frequently used for myocarditis (22 of 44 patients; 50%). Techniques included 25 vents, 17 static balloon dilations, and two stents. All techniques were equally successful and significantly reduced left atrial pressure and pulmonary edema. Survival to hospital discharge was not associated with extracorporeal membrane oxygenation duration prior to left atrial decompression, change in left atrial pressure, or technique used. Persistent atrial septal defect was noted in five surviving patients (excluding transplant recipients and deceased), two required closure. CONCLUSIONS: Left atrial decompression can be performed effectively in children on extracorporeal membrane oxygenation using various percutaneous techniques. Reduction in pulmonary venous congestion is usually evident by chest radiography within 48 hours of intervention. Persistent atrial septal defect may require closure at the time of extracorporeal membrane oxygenation decannulation or during long-term follow-up.

Technical challenges of atrial septal stent placement in fetuses with hypoplastic left heart syndrome and intact atrial septum.

OBJECTIVES: The objective of this study was to describe our single-institution experience with prenatal atrial septal stent placement for fetuses with hypoplastic left heart syndrome and an intact atrial septum (HLHS/IAS). BACKGROUND: Infants born with HLHS/IAS are at high risk for neonatal death, despite maximal postnatal therapy. Prenatal atrial septoplasty by static balloon dilation has been effective in decompressing the left atrium (LA) in utero, but several factors have limited the size of septal defects. We attempted to overcome the limitations of balloon septoplasty using transcatheter atrial septal stents. METHODS: All records from our institution of fetuses with HLHS/IAS that underwent prenatal atrial septal stent placement were reviewed, including operative notes and echocardiograms. RESULTS: Nine fetuses between 24 and 31 weeks gestation with HLHS/IAS underwent attempted fetal atrial septal stent placement. A stent was deployed across the atrial septum in five fetuses, with four fetuses demonstrating flow across the stent at the time of intervention. In four cases, stent placement failed due to malposition or embolization, but in three of the four cases, atrial balloon septoplasty at the same in-utero procedure successfully and acutely decompressed the LA. There were no maternal complications. There was one fetal demise. The remaining eight fetuses survived to delivery, but four died in the neonatal period (two of which had been stented). CONCLUSIONS: Ultrasound-guided atrial septal stent placement is feasible in some fetuses with HLHS/IAS. Visualization of the septum and catheter tip is critical to technical success. Additional experience is necessary to determine the clinical impact of this intervention. © 2013 Wiley Periodicals, Inc.

Mixed aortic valve disease in the young: initial observations.

The short-term surgical results for mixed aortic valve disease (MAVD) and the long-term effects on the left ventricle (LV) are unknown. Retrospective review identified patients with at least both moderate aortic stenosis (AS) and aortic regurgitation (AR) before surgical intervention. A one-to-one comparison cohort of patients with MAVD not referred for surgical intervention was identified. The 45 patients in this study underwent surgical management for MAVD. A control group of 45 medically managed patients with MAVD also was identified. Both groups had elevated LV end-diastolic volume (EDV), elevated LV mass, a normal LV mass:volume ratio (MVR), and a normal ejection fraction. Both groups had diastolic dysfunction shown by early diastolic pulsed-Doppler mitral inflow/early diastolic tissue Doppler velocity z-score. The LV end-diastolic pressure (EDP) was correlated with age (R = 0.4; p = 0.03) and LV MVR (R = 0.4; p = 0.03) but not with AS, AR, or the score combining gradient and LV size. As shown by 6- to 12-month postoperative echocardiograms, aortic valve gradients and AR significantly improved (gradient 65 ± 17 to 28 ± 18 mmHg, p = 0.01; median regurgitation grade moderate to mild; p < 0.01), LV EDV normalized, and LV mass significantly improved (p < 0.01). Diastolic dysfunction was unchanged. Symptoms did not correlate with any measured parameter, but the preoperative symptoms resolved. In conclusion, despite diastolic dysfunction, systolic function is invariably preserved, and symptoms are not correlated with aortic valve function or LV EDP. Current surgical practice preserves LV mechanics and results in short-term improvement in valve function and symptoms.

Bare metal stenting for obstructed small diameter homograft conduits in the right ventricular outflow tract.

OBJECTIVE: Our aim was to assess acute hemodynamic changes with stent insertion, outcomes, and factors associated with increased longevity of stented small diameter homograft conduits. BACKGROUND: Right ventricle-to-pulmonary artery (RV-PA) homograft conduits are commonly used to palliate RV outflow tract obstruction. Bare metal stenting (BMS) and transcatheter pulmonary valve implantation have been shown to relieve obstructed larger diameter conduits and may delay surgical conduit reintervention. Less is known about BMS of small conduits. METHODS AND RESULTS: From 1992 to 2009, BMS was performed to relieve obstruction in 106 homograft conduits that were ≤12 mm at implant. The peak RV-PA gradient fell from 54.3 ± 17.4 mm Hg at baseline to 46.1 ± 15.2 mm Hg after balloon dilation alone and to 25.1 ± 11.4 mm Hg with stenting (all P < 0.001). Higher pre-BMS gradient and RV pressure were the only factors associated with higher post-BMS RV-PA gradient (≥30 mm Hg; both P < 0.001). There were no procedural deaths, two patients required surgical removal of embolized stents. At a median follow-up of 1.6 years, 83 conduits were replaced; freedom from conduit reoperation after BMS was 66% ± 5% at 1 year and 28% ± 5% at 3 years. Factors associated with shorter freedom from reoperation included implanted conduit diameter <10 mm (P = 0.009), higher post-stent RV-PA gradient (P = 0.026), and higher post-stent RV pressure (P < 0.01); only post-stent RV pressure remained significant on multivariable analysis (P < 0.001). CONCLUSION: BMS was acutely effective for the treatment of obstructed small diameter homograft conduits, with low morbidity. Prolongation of small diameter homograft conduit longevity with BMS may be useful in the lifetime management of conduit dysfunction in this patient population.

Midaortic syndrome: 30 years of experience with medical, endovascular and surgical management.

BACKGROUND: Midaortic syndrome is often associated with refractory hypertension. The aim of our study was to better understand the short- and medium-term outcomes in this patient population utilizing a multidisciplinary management approach. METHODS: We conducted a review of patients with midaortic syndrome treated at our institution over the past 30 years. RESULTS: Fifty-three patients presented at a median age of 6.7 years (birth to 28.7 years). Thirty-five patients (66 %) underwent invasive management (percutaneous techniques: 21; surgical techniques: 5; both: 9). Percutaneous interventions were acutely successful in decreasing the gradient across the obstruction and degree of luminal stenosis. However, freedom from reintervention was 58 % at 1 year and 33 % at 5 years. Freedom from reintervention after a surgical procedure was longer: 83 % at 1 year and 72 % at 10 years. At the most recent follow-up, the majority of patients (69 %) were normotensive. The median duration between time of presentation and achievement of blood pressure control was 5.7 (0.4-21.1) years. The median number of anti-hypertensive medications was 1 (0-5). CONCLUSIONS: A multidisciplinary management strategy which couples comprehensive medical management with catheter-based and surgical interventions can lead to adequate blood pressure control and preservation of end-organ function in patients with midaortic syndrome.

Obstruction of the superior vena cava after neonatal extracorporeal membrane oxygenation: association with chylothorax and outcome of transcatheter treatment.

BACKGROUND: Obstruction of the superior vena cava is one of the potential complications of neonatal extracorporeal membrane oxygenation. Chylothorax is a known complication of surgery involving the thoracic cavity in children, and of extracorporeal membrane oxygenation. The aim of this study was to evaluate the association between chylothorax and superior vena cava obstruction after neonatal extracorporeal membrane oxygenation. METHODS AND RESULTS: Twenty-two patients diagnosed with superior vena cava obstruction at ≤ 6 months of age (median 1.8 months) after neonatal extracorporeal membrane oxygenation were compared with a randomly selected cohort of 44 neonatal extracorporeal membrane oxygenation patients without superior vena cava obstruction. Among patients with superior vena cava obstruction, 18 underwent extracorporeal membrane oxygenation for respiratory disease and four for cardiac insufficiency. Chylothorax was more prevalent among patients with superior vena cava obstruction than controls (odds ratio 9.4 [2.2-40], p = .01) and was associated with extension of obstruction into the left innominate vein. Patients with superior vena cava obstruction were supported by extracorporeal membrane oxygenation for a longer duration than controls. Nineteen patients with superior vena cava obstruction (86%) underwent transcatheter balloon angioplasty and/or stent implantation (median 7 days after diagnosis), which decreased the superior vena cava pressure and superior vena cava-to-right atrium pressure gradient and increased the superior vena cava diameter (all p < 0.001). There were no serious procedural adverse events. Six study patients died within 30 days of the diagnosis of superior vena cava obstruction (including three of nine with chylothorax), which did not differ from controls. During a median follow-up of 2.7 yrs, two additional patients died and nine underwent 14 superior vena cava reinterventions. CONCLUSIONS: Among neonates treated with extracorporeal membrane oxygenation, superior vena cava obstruction is associated with an increased risk of chylothorax. In neonates with chylothorax after extracorporeal membrane oxygenation, evaluation for superior vena cava obstruction may be warranted. Although mortality is high in this population, transcatheter treatment can relieve superior vena cava obstruction and facilitate symptomatic improvement.

Short- and medium-term outcomes after transcatheter pulmonary valve placement in the expanded multicenter US melody valve trial.

BACKGROUND: Transcatheter pulmonary valve placement is an emerging therapy for pulmonary regurgitation and right ventricular outflow tract obstruction in selected patients. The Melody valve was recently approved in the United States for placement in dysfunctional right ventricular outflow tract conduits. METHODS AND RESULTS: From January 2007 to August 2009, 136 patients (median age, 19 years) underwent catheterization for intended Melody valve implantation at 5 centers. Implantation was attempted in 124 patients; in the other 12, transcatheter pulmonary valve placement was not attempted because of the risk of coronary artery compression (n=6) or other clinical or protocol contraindications. There was 1 death from intracranial hemorrhage after coronary artery dissection, and 1 valve was explanted after conduit rupture. The median peak right ventricular outflow tract gradient was 37 mm Hg before implantation and 12 mm Hg immediately after implantation. Before implantation, pulmonary regurgitation was moderate or severe in 92 patients (81% with data); no patient had more than mild pulmonary regurgitation early after implantation or during follow-up (>or=1 year in 65 patients). Freedom from diagnosis of stent fracture was 77.8+/-4.3% at 14 months. Freedom from Melody valve dysfunction or reintervention was 93.5+/-2.4% at 1 year. A higher right ventricular outflow tract gradient at discharge (P=0.003) and younger age (P=0.01) were associated with shorter freedom from dysfunction. CONCLUSIONS: In this updated report from the multicenter US Melody valve trial, we demonstrated an ongoing high rate of procedural success and encouraging short-term valve function. All reinterventions in this series were for right ventricular outflow tract obstruction, highlighting the importance of patient selection, adequate relief of obstruction, and measures to prevent and manage stent fracture. Clinical Trial Registration- URL: http://www.clinicaltrials.gov. Unique identifier: NCT00740870.

Predictors of technical success and postnatal biventricular outcome after in utero aortic valvuloplasty for aortic stenosis with evolving hypoplastic left heart syndrome.

BACKGROUND: Aortic stenosis in the midgestation fetus with a normal-sized or dilated left ventricle predictably progresses to hypoplastic left heart syndrome when associated with certain physiological findings. Prenatal balloon aortic valvuloplasty may improve left heart growth and function, possibly preventing evolution to hypoplastic left heart syndrome. METHODS AND RESULTS: Between March 2000 and October 2008, 70 fetuses underwent attempted aortic valvuloplasty for critical aortic stenosis with evolving hypoplastic left heart syndrome. We analyzed this experience to determine factors associated with procedural and postnatal outcome. The median gestational age at intervention was 23 weeks. The procedure was technically successful in 52 fetuses (74%). Relative to 21 untreated comparison fetuses, subsequent prenatal growth of the aortic and mitral valves, but not the left ventricle, was improved after intervention. Nine pregnancies (13%) did not reach a viable term or preterm birth. Seventeen patients had a biventricular circulation postnatally, 15 from birth. Larger left heart structures and higher left ventricular pressure at the time of intervention were associated with biventricular outcome. A multivariable threshold scoring system was able to discriminate fetuses with a biventricular outcome with 100% sensitivity and modest positive predictive value. CONCLUSIONS: Technically successful aortic valvuloplasty alters left heart valvar growth in fetuses with aortic stenosis and evolving hypoplastic left heart syndrome and, in a subset of cases, appeared to contribute to a biventricular outcome after birth. Fetal aortic valvuloplasty carries a risk of fetal demise. Fetuses undergoing in utero aortic valvuloplasty with an unfavorable multivariable threshold score at the time of intervention are very unlikely to achieve a biventricular circulation postnatally.

Comparison of conventional and cutting balloon angioplasty for congenital and postoperative pulmonary vein stenosis in infants and young children.

BACKGROUND: Pulmonary vein stenosis (PVS) is a rare and often lethal condition in children. The optimal treatment for congenital and postoperative PVS is unknown. METHODS AND RESULTS: We compared outcomes of conventional balloon angioplasty performed for PVS from 1999 to 2003 against cutting balloon angioplasty performed from 2004 to 2007. A total of 100 previously undilated pulmonary veins in 54 patients were studied: 48 veins dilated with conventional balloons and 52 with cutting balloons. Acute results included significantly reduced gradients and increased lumen diameters with both treatments. Acutely, cutting balloon angioplasty and conventional angioplasty yielded similar relative reduction of the PVS gradient (median 78% vs. 63%, P = 0.08) and increase in lumen diameter (median 77% vs. 59%, P = 0.07). There was one procedural death of a critically ill infant, and four cardiac arrests, but no adverse events necessitating surgical intervention. Survival free from reintervention was poor in both groups, and shorter in the cutting balloon group (73% at 1 month, 11% at 6 months, and 4% at 1 year) than in the conventional angioplasty group (77% at 1 month, 35% at 6 months, and 23% at 1 year; P = 0.01). CONCLUSIONS: Both conventional and cutting balloon angioplasty were effective at decreasing gradient and increasing lumen size acutely in patients with congenital and postoperative PVS, but reintervention was common with both treatments. Both methods of angioplasty provided limited benefit, and neither was curative for this complex disease.

Long-term survival, modes of death, and predictors of mortality in patients with Fontan surgery.

BACKGROUND: To better define determinants of mortality in patients with univentricular physiology, a database registry was created of patients born in 1985 or earlier with Fontan surgery who were followed up at Children's Hospital Boston. METHODS AND RESULTS: A total of 261 patients, 121 of whom (46.4%) were women, had a first Fontan surgery at a median age of 7.9 years: right atrium-to-pulmonary artery connection in 135 (51.7%); right atrium to right ventricle in 25 (9.6%); and total cavopulmonary connection in 101 (38.7%). Over a median of 12.2 years, 76 (29.1%) died, 5 (1.9%) had cardiac transplantation, 5 (1.9%) had Fontan revision, and 21 (8.0%) had Fontan conversion. Perioperative mortality decreased steadily over time and accounted for 68.4% of all deaths. In early survivors, actuarial freedom from death or transplantation was 93.7%, 89.9%, 87.3%, and 82.6% at 5, 10, 15, and 20 years, respectively, with no significant difference between right atrium to pulmonary artery versus total cavopulmonary connection. Late deaths were classified as sudden in 7 patients (9.2%), thromboembolic in 6 (7.9%), heart failure-related in 5 (6.7%), sepsis in 2 (2.6%), and other in 4 (5.2%). Most sudden deaths were of presumed arrhythmic origin with no identifiable predictor. Independent risk factors for thromboembolic death were lack of antiplatelet or anticoagulant therapy (hazard ratio [HR], 91.6; P=0.0041) and clinically diagnosed intracardiac thrombus (HR, 22.7; P=0.0002). Independent predictors of heart failure death were protein-losing enteropathy (HR, 7.1; P=0.0043), single morphologically right ventricle (HR, 10.5; P=0.0429), and higher right atrial pressure (HR, 1.3 per 1 mm Hg; P=0.0016). CONCLUSIONS: In perioperative survivors of Fontan surgery, gradual attrition occurs predominantly from thromboembolic, heart failure-related, and sudden deaths.

Contrast administration in pediatric cardiac catheterization: dose and adverse events.

BACKGROUND: In pediatrics, contrast-related AE such as allergic reactions, seizures, and nephropathy have been reported to occur after cardiac catheterization, but their incidence remains unknown. OBJECTIVE: We sought to report adverse event (AE) rates attributed to contrast administration in a pediatric cardiac catheterization lab and identify characteristics related to higher doses. METHODS: A single institution prospective cardiac catheterization AE database identified AE in children <18 years old exposed to contrast. All AE were reviewed and classified by relationship to contrast. Medical records for the 50 cases who received highest contrast doses were retrospectively reviewed for AE. Patient and procedural characteristics were compared in the top quartile of contrast dose versus remaining cases. RESULTS: Over 3 years, 2,321 consecutive cases required median 3.9 cm(3)/kg [IQR: 2.0, 6.0] of contrast. Patients receiving high dose contrast (top quartile) were more likely to be <1 year (51% vs. 24%), weigh <10 kg (66% vs. 29%), have complex 2 ventricle disease (56% vs. 35%), be in a high procedure type risk group (57% vs. 26%), and undergo procedures >2 h (67% vs. 28%), all P < 0.001. Only 2 of 2,321 cases (0.09%, 95% CI 0.01-0.31%) had AE possibly related to contrast. These events were an acute neurological change and transient nephropathy. In 50 cases receiving the most contrast, no AE were attributed to contrast. CONCLUSION: A large volume pediatric cardiac catheterization lab administered >or= 6 cm(3)/kg of contrast in a quarter of cases; however, AE related to contrast exposure were exceedingly rare.

Risk stratification, systematic classification, and anticipatory management strategies for stent fracture after percutaneous pulmonary valve implantation.

BACKGROUND: We analyzed the incidence, risk factors and treatment options for stent fracture after percutaneous pulmonary valve (PPV) implantation (PPVI). METHODS AND RESULTS: After PPVI, 123 patients had chest x-ray in anteroposterior and lateral projection, echocardiography, and clinical evaluation during structured follow-up. Of these 123 patients, 26 (21.1%) developed stent fracture 0 to 843 days after PPVI (stent fracture-free survival at 1 year, 85.1%; at 2 years, 74.5%; and at 3 years, 69.2%). Stent fracture was classified as type I: no loss of stent integrity (n=17); type II: loss of integrity with restenosis on echocardiography (n=8); and type III: separation of fragments or embolization (n=1). In a multivariate Cox regression, we analyzed various factors, of which 3 were associated with a higher risk of stent fracture: implantation into "native" right ventricular outflow tract (P=0.04), no calcification along the right ventricular outflow tract (judged with fluoroscopy, P=0.02), recoil of PPV (qualitatively, PPV diameter in frontal or lateral plane with fully inflated balloon > diameter after balloon deflation, P=0.03). Substernal PPV location, high-pressure post-PPVI dilatation of PPV, pre-PPVI right ventricular outflow tract gradients, and other indicators of PPV compression or asymmetry did not pose increased risk. Patients with type I fracture remain under follow-up. Patients with type II fracture had 2nd PPVI or are awaiting such procedure, and 1 patient with type III fracture required surgical explantation. CONCLUSIONS: Stent fracture after PPVI can be managed effectively by risk stratification, systematic classification, and anticipatory management strategies. Serial x-ray and echocardiography are recommended for surveillance.