Doppler Echocardiographic Features of Pulmonary Vein Stenosis in Ex-Preterm Children.

BACKGROUND: Echocardiography is used to screen for the presence of pulmonary vein stenosis (PVS) in ex-preterm infants and children. However, there are no standard accepted criteria for screening or diagnosis of PVS by echocardiography. The aim of this study was to identify Doppler waveform features and Doppler systolic and diastolic velocity cutoff values associated with a diagnosis of PVS by cardiac catheterization. METHODS: In this retrospective observational study, the echocardiograms of ex-preterm children <3 years old who underwent cardiac catheterization at a single institution were reviewed. PVS on cardiac catheterization was defined by a mean pressure gradient of >3 mm Hg in the pulmonary vein, with angiographic evidence of stenosis. Pulmonary vein Doppler waveforms, from echocardiograms obtained before catheterization, in children with and without PVS were compared. Nonstenosed veins in patients with PVS were excluded. The systolic and diastolic velocities of blood flow, phasic flow, and return of the Doppler waveform to baseline were analyzed. RESULTS: Forty-seven children were analyzed in the study, 18 children with 25 stenosed pulmonary veins and 29 children with 78 nonstenosed pulmonary veins. Stenosed pulmonary veins had higher peak systolic and diastolic velocities and higher peak and mean pressure gradients as measured by spectral Doppler. Peak systolic and diastolic velocities had areas under the receiver operating characteristic curve of 0.89 (95% CI, 0.79-0.99) and 0.93 (95% CI, 0.85-0.99) for PVS, respectively, and a threshold velocity of 0.7 m/sec had sensitivity of 80% and 84% and specificity of 94%. There was no correlation between Doppler-derived pulmonary vein mean gradient and measured pulmonary vein mean gradient during cardiac catheterization in stenosed pulmonary veins. Presence of phasic flow in the pulmonary vein and return of the Doppler waveform to baseline were associated with a nonstenosed pulmonary vein (sensitivity of 94% and 60% and specificity of 52% and 60%, respectively). CONCLUSIONS: Systolic and diastolic Doppler velocities and features of the waveform can discriminate stenosed pulmonary veins confirmed by cardiac catheterization in ex-preterm children. These results suggest the use of lower systolic and diastolic Doppler velocity cutoff values than currently published to screen for PVS in ex-preterm children. These cutoff values require validation in prospective studies.

Development and Utility of Quality Metrics for Ambulatory Pediatric Cardiology in Kawasaki Disease.

The Adult Congenital and Pediatric Cardiology (ACPC) Section of the American College of Cardiology sought to develop quality indicators/metrics for ambulatory pediatric cardiology practice. The objective of this study was to report the creation of metrics for patients with Kawasaki disease. Over a period of 5 months, 12 pediatric cardiologists developed 24 quality metrics based on the most relevant statements, guidelines, and research studies pertaining to Kawasaki disease. Of the 24 metrics, the 8 metrics deemed the most important, feasible, and valid were sent on to the ACPC for consideration. Seven of the 8 metrics were approved using the RAND method by an expert panel. All 7 metrics approved by the ACPC council were accepted by ACPC membership after an "open comments" process. They have been disseminated to the pediatric cardiology community for implementation by the ACPC Quality Network.

Detection rates of congenital heart disease in Guatemala.

OBJECTIVES: In developing countries, congenital heart disease is often unrecognised, leading to serious morbidity and mortality. Guatemala is one of the few developing countries where expert paediatric cardiac treatment is available and affordable, and therefore early detection could significantly improve outcome. We assessed regional congenital heart disease detection rates in Guatemala, and determined whether they correlated with the regional human development index. METHODS: We retrospectively reviewed all new cardiac referrals made in 2006 to the Unidad de Cirugia Cardiovascular Pediatrica, the only paediatric cardiac centre in Guatemala. We calculated regional detection rates by comparing the number of congenital heart disease referrals with the expected incidence using the National Ministry of Health birth data. We then compared the regional detection rates with the human development index data published in the United Nations 2006 Development Program Report using Spearman's rank correlation. RESULTS: An estimated 3935 infants with cardiac defects were born in Guatemala in 2006, an expected 1380 (35%) of whom had severe forms. Overall, only 533 children (14%) with cardiac defects were referred. Of these, 62% had simple shunt lesions, 13% had cyanotic lesions, and 10% had left-sided obstructive lesions. Only 11.5% of referred patients were neonates. Regional detection rates, ranged 3.2-34%, correlated with the regional human development index (r = 0.75, p < 0.0001). CONCLUSIONS: Current detection of congenital heart disease in Guatemala is low and correlates with the regional human development index. Those detected are older and have less severe forms, suggesting a high mortality rate among Guatemalan neonates with complex cardiac defects.

Peripheral arterial function in infants and young children with one-ventricle physiology and hypoxemia.

Patients with 1-ventricle (1V) physiology may be at risk for peripheral arterial dysfunction at a young age. To determine whether infants and young children with 1V physiology and hypoxemia have peripheral arterial dysfunction before undergoing the Fontan operation, we measured (1) flow-mediated vasodilation (FMD) in the brachial artery, (2) serum levels of vasoactive mediators endothelin-1 (ET-1) and metabolites of nitric oxide, and (3) arterial stiffness with pulse-wave velocity (PWV) in the aorta. Eighteen patients with 1V physiology before the Fontan procedure and hypoxemia and 19 patients with normoxemia and 2-ventricle (2V) physiology were studied. Measurements were collected during cardiac catheterization. FMD in the brachial artery was the diameter gain after 4.5 minutes of forearm occlusion measured with high-resolution ultrasound and edge-detection software. Nitric oxide and ET-1 levels were measured in venous blood. PWV between the left carotid and femoral arteries was measured using pulse Doppler ultrasound. FMD was lower (2.4 +/- 3.7% vs 11.3 +/- 6%, p <0.0005) and ET-1 levels were higher (35.5 +/- 11.3% vs 24.1 +/- 9.7%, p = 0.003) in subjects with 1V physiology versus those with 2V physiology, respectively. There were no differences in nitric oxide levels or PWV. In conclusion, infants and young children with 1V physiology and hypoxemia have blunted FMD and higher ET-1 levels before undergoing the Fontan operation compared with normoxemic subjects with 2V physiology. A further understanding of pathophysiologic mechanisms underlying peripheral arterial dysfunction, including the roles of hypoxemia, low cardiac index, and ET-1, may lead to targeted therapies and improve the long-term survival of patients with 1V physiology.

Ductus-associated proximal pulmonary artery stenosis in patients with right heart obstruction.

Proximal pulmonary artery stenosis is a common acquired lesion in infants treated for congenital heart disease. We hypothesized that a large number of stenoses develop at the site of ductal insertion in patients with right ventricular outflow tract obstruction (RVOTO) and that these patients are at risk for developing hypoplasia of the ipsilateral pulmonary artery. The surgical and cardiac catheterization databases at our institution during the years 1988-2000 were searched for all patients under 1 year of age carrying a diagnosis of pulmonary atresia with intact ventricular septum (PA), tetralogy of Fallot (TOF) or pulmonary stenosis (PS), yielding 700 patients (62 PA, 373 TOF, 265 PS). The cardiac catheterization database was also searched for all patients with any diagnosis under 1 year of age found at catheterization to have proximal pulmonary artery stenosis. Proximal pulmonary artery stenosis associated with the ductal insertion site was diagnosed at catheterization in 33 infants (18 with PA, 5 with TOF, 6 with PS, 4 other diagnoses). This represents 29% of patients with PA, 1% with TOF and 2% with PS. Among patients with RVOTO and ductal insertion site-associated stenosis, there was a high prevalence (59%) of associated distal pulmonary arterial hypoplasia, defined as diameter of the stenosed vessel at first distal branch < or = 80% the diameter of the contralateral vessel. Symptomatology failed to identify this lesion; therefore, a high index of suspicion is necessary if proximal pulmonary artery stenosis is to be detected early in these patients.

Combined pulmonary stenosis and insufficiency preserves myocardial contractility in the developing heart of growing swine at midterm follow-up.

This study was conducted to determine the effects of chronic combined pulmonary stenosis and pulmonary insufficiency (PSPI) on right (RV) and left ventricular (LV) function in young, growing swine. Six pigs with combined PSPI were studied, and data were compared with previously published data of animals with isolated pulmonary insufficiency and controls. Indexes of systolic function (stroke volume, ejection fraction, and cardiac functional reserve), myocardial contractility (slope of the end-systolic pressure-volume and change in pressure over time-end-diastolic volume relationship), and diastolic compliance were assessed within 2 days of intervention and 3 mo later. Magnetic resonance imaging was used to quantify pulmonary insufficiency and ventricular volumes. The conductance catheter was used to obtain indexes of the cardiac functional reserve, diastolic compliance, and myocardial contractility from pressure-volume relations acquired at rest and under dobutamine infusion. In the PSPI group, the pulmonary regurgitant fraction was 34.3 +/- 5.8%, the pressure gradient across the site of pulmonary stenosis was 20.9 +/- 20 mmHg, and the average RV peak systolic pressure was 70% systemic at 12 wk follow-up. Biventricular resting cardiac outputs and cardiac functional reserves were significantly limited (P < 0.05), LV diastolic compliance significantly decreased (P < 0.05), but RV myocardial contractility significantly enhanced (P < 0.05) compared with control animals at 3-mo follow-up. In the young, developing heart, chronic combined PSPI impairs biventricular systolic pump function and diastolic compliance but preserves RV myocardial contractility.

Retrograde transcatheter coil embolization of congenital coronary artery fistulas in infants and young children.

We report the success of transcatheter coil embolization of congenital coronary artery fistulas in infants and young children, primarily using a retrograde coaxial delivery system. Transcatheter coil embolization of coronary artery fistulas has been used successfully in the adult population with limited reports in the pediatric population, especially in infants. Ten patients underwent transcatheter coil embolization of congenital coronary artery fistulas between January 1993 and August 1999. The median age was 4.5 years (ranging from 5 weeks to 9.8 years). Coils were delivered exclusively using a retrograde arterial approach in 8 of 10 patients. A coaxial system was used in 8 patients. Angiography immediately after placement of coils revealed no residual shunt in any patient. Recent follow-up evaluation is available for 9 patients (median duration of follow-up, 7.9 months). Echocardiographic and clinical evaluations show complete occlusion in 8 of 9 patients. All patients are asymptomatic with normalization of chamber dimensions and coronary artery caliber. Transcatheter coil embolization of congenital coronary artery fistulas can be performed safely and successfully in infants and young children. The use of a retrograde approach and coaxial system is safe and effective and may provide better accuracy, stability and precision for placement of coils.

Surgical creation of aortopulmonary window in selected patients with pulmonary atresia with poorly developed aortopulmonary collaterals and hypoplastic pulmonary arteries.

OBJECTIVE: The morphologic characteristics of the pulmonary circulation vary widely in patients with pulmonary atresia, ventricular septal defect, and major aortopulmonary collaterals. Although we favor single-stage unifocalization and complete repair as the procedure of choice, a subgroup of patients who meet specific criteria have been treated with initial surgical creation of an aortopulmonary window. METHODS: Eighteen patients who were considered unsuitable candidates for single-stage repair underwent surgical creation of an aortopulmonary window. Selection criteria included the following: (1) presence of centrally confluent true pulmonary arteries 1.0 to 2.5 mm in diameter, with a well-developed peripheral arborization pattern; (2) multiple small aortopulmonary collateral vessels, most of which communicated with the true pulmonary arterial system; and (3) the presence of marked cyanosis. RESULTS: There were no early deaths, and the 2 late deaths were both unrelated to the procedure. Follow-up angiography (n = 17) demonstrated good growth of true pulmonary arteries in 15 of 17 cases (88%). Mean pulmonary artery diameter increased from 1.76 mm to 3.45 mm. Subsequent operations have been performed in 15 of 18 cases (83%). Intracardiac repair with or without additional unifocalization was achieved in 8 of these 15 (53%). Seven patients (47%) have undergone staged unifocalization as the next procedure; of these, 3 were able to have intracardiac repair. Thus 11 of the 15 patients who have undergone second operations (73%) have had complete intracardiac repair. CONCLUSIONS: The initial surgical creation of an aortopulmonary window in carefully selected patients can increase the size of the true pulmonary arteries, making these patients better candidates for eventual intracardiac repair. The procedure should be avoided in patients with pulmonary overcirculation, a predominance of isolated supply collaterals, or true pulmonary arteries larger than 2.5 mm in diameter, and it is not applicable without a true pulmonary artery central confluence.

Use of small stents for rehabilitation of hypoplastic pulmonary arteries in pulmonary atresia with ventricular septal defect.

Branch pulmonary artery stenosis frequently occurs in pulmonary atresia with ventricular septal defect (PA/VSD). Balloon dilation alone is often unsuccessful in patients with severely hypoplastic pulmonary arteries with residual stenoses after surgical repair. In an attempt to promote distal pulmonary artery growth, 17 stents were placed in 12 severely stenotic pulmonary artery lesions in 10 patients with PA/VSD. All had prior surgery, including pulmonary artery repair, right ventricle to pulmonary artery homograft, and, in 6 of 10, closure of VSD. Median age at stent placement was 16.8 months (range, 13.2-56). Stents were placed using 3.0, 3.5, or 4.0 mm balloons in all but one lesion, in which a 7 mm balloon was used. Following stent placement, there was an increase in the lesion diameter from 1.5 to 3.4 mm (P < 0.05) and an increase in flow to the affected lung from 27% to 34% (P < 0.05). Repeat catheterization 2 to 6 months after stenting in six patients revealed complete occlusion in two of eight lesions. In the other six vessels, there was an increase in distal vessel diameter from 2.96 to 3.94 mm (P < 0.05) even though four had severe restenosis requiring restenting. Two patients underwent surgical pulmonary artery reconstruction and stent removal because of adequate distal vessel growth. Stenting of hypoplastic pulmonary arteries in PA/VSD results in immediate improvement in vessel size and blood flow. Stent restenosis is common although distal vessel growth can be achieved. Stenting of these lesions should be reserved only for those patients unresponsive to other interventions.