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Background: Extreme preterm birth confers risk of long-term impairments in lung function and exercise capacity. There are limited data on the factors contributing to exercise limitation following extreme preterm birth. This study examined respiratory mechanics and ventilatory response during exercise in a large cohort of children born extremely preterm (EP).Methods: This cohort study included children 8-12 years of age who were born EP (≤28 weeks gestation) between 1997 and 2004 and treated in a large regionalised neonatal intensive care unit in western Canada. EP children were divided into no/mild bronchopulmonary dysplasia (BPD) (ie, supplementary oxygen or ventilation ceased before 36 weeks gestational age; n=53) and moderate/severe BPD (ie, continued supplementary oxygen or ventilation at 36 weeks gestational age; n=50). Age-matched control children (n=65) were born at full term. All children attempted lung function and cardiopulmonary exercise testing measurements.Results: Compared with control children, EP children had lower airway flows and diffusion capacity but preserved total lung capacity. Children with moderate/severe BPD had evidence of gas trapping relative to other groups. The mean difference in exercise capacity (as measured by oxygen uptake (VO2)% predicted) in children with moderate/severe BPD was -18±5% and -14±5.0% below children with no/mild BPD and control children, respectively. Children with moderate/severe BPD demonstrated a potentiated ventilatory response and greater prevalence of expiratory flow limitation during exercise compared with other groups. Resting lung function did not correlate with exercise capacity.Conclusions: Expiratory flow limitation and an exaggerated ventilatory response contribute to respiratory limitation to exercise in children born EP with moderate/severe BPD. [ABSTRACT FROM AUTHOR]

Fetal and neonatal Ebstein's anomaly has a poor prognosis, and there are few contemporary reviews of management and outcomes. This study retrospectively reviewed a management algorithm promoting early ductal closure after anatomic pulmonary obstruction had been excluded or relieved in neonatal Ebstein's anomaly from 1995 to 2004. Twenty-eight patients with Ebstein's anomaly were identified, 9 prenatally (8 with hydrops) and 19 postnatally, at a median age of <24 hours. Celermajer index scores predicted a mortality rate of 35%. Prostaglandins were administered to 24 of 28 patients. Prostaglandins were continued for obstructive lesions in 9 until the relief of pulmonary outflow obstructions or aortic coarctation repair. In 8 of 9 patients, prostaglandins were discontinued after intervention. One patient continued receiving prostaglandins until a Blalock-Taussig shunt was performed 3 weeks after surgical valvotomy. Prostaglandins were discontinued in 17 of 24 patients with uneventful ductal constrictions. The ductus arteriosus persisted in 5 patients with hemodynamic instability, of whom 4 underwent ductal ligation, with immediate improvement. In 1 of 24 patients, unrecognized right ventricular outflow tract obstructions became apparent when prostaglandins were discontinued. Prostaglandins were restarted until a primary superior cavopulmonary anastomosis was performed at 7 weeks. The median follow-up period of 26 survivors was 34 months (range 3 to 106), 4 after bidirectional superior cavopulmonary anastomoses and 1 after a Fontan procedure. In conclusion, in neonatal Ebstein's anomaly of the tricuspid valve, prolonged patency of the ductus arteriosus in patients without anatomic outflow tract obstructions is deleterious. "Circular shunts" may develop in patients with pulmonary and tricuspid insufficiency. The ligation or spontaneous constriction of the ductus arteriosus may result in hemodynamic improvement. This approach to neonatal Ebstein's anomaly of the tricuspid valve has yielded a substantial reduction in mortality to 7% in a high-risk cohort. [ABSTRACT FROM AUTHOR]

Alveolar capillary dysplasia is a fatal disorder of the lung that requires lung biopsy for diagnosis. We reviewed the course of patients with alveolar capillary dysplasia following implementation of an early lung biopsy strategy between 1997-2002. We performed immunohisto-chemical studies on all tissue specimens. We diagnosed 7 cases of alveolar capillary dysplasia. We diagnosed 6/7 cases of alveolar capillary dysplasia pre-mortem by early lung biopsy. Median time between admission and lung biopsy was 6.5 days. All patients survived lung biopsy but died following withdrawal of active therapy after confirmation of the tissue diagnosis. In 1 patient we demonstrated histological findings of alveolar capillary dysplasia and congenital acinar dysplasia. Two patients were first cousins. One patient underwent pulmonary angiography with rapid filling of the pulmonary veins before passage of contrast through the capillary bed. Five patients were supported with extracorporeal membrane oxygenation and 2/5 patients survived decannulation. During the same period 8 patients required ECMO for acute hypoxic respiratory failure. Four out of 8 were diagnosed with alveolar capillary dysplasia. CONCLUSIONS: Early lung biopsy was performed with low risk and high diagnostic yield for alveolar capillary dysplasia. Alveolar capillary dysplasia occurs frequently in neonates who require ECMO support for refractory pulmonary hypertension. We have added an additional familial case and suggest a novel angiographic finding. [ABSTRACT FROM AUTHOR]

OBJECTIVE--To investigate the effect of intracardiac repair on the abnormal biosynthesis of prostacyclin (PGI2) and thromboxane A2 (TXA2) in children with congenital heart disease and increased pulmonary blood flow. DESIGN--A prospective study with immunoaffinity chromatography and gas chromatography-mass spectrometry to measure the urinary excretion products of PGI2 (2,3-dinor-6-oxo-prostaglandin (PG) F1 alpha (2,3-dinor-6-oxo-PGF1 alpha)) and TXA2 (2,3-dinor-TXB2) before operation, in the first 12-24 h after operation, and at discharge from hospital. SETTING--A supraregional referral centre for patients with congenital heart disease. PATIENTS--15 patients aged 2 to 60 months (median 7 months) with a left to right shunt who underwent intracardiac repair. RESULTS--The preoperative 2,3-dinor-TXB2 excretion rate was greater than that found previously in a control group of 16 healthy children with a median (range) age of 24 (6-36) months (1159(201) v 592(122) ng/g creatinine in controls, P = 0.006). The excretion rate rose after operation to 9600(3832) ng/g creatinine (P = 0.01) and decreased before discharge to 1071(191) ng/g creatinine (NS), but remained greater than that of the control group (P = 0.014). Before operation 2,3-dinor-6-oxo-PGF1 alpha excretion rates were similar to those of the healthy children (482(68) v 589(95) ng/g creatinine in controls) but increased after operation to 19,668(11,162) ng/creatinine (P = 0.002) and fell at discharge to 1621(245) ng/g creatinine although this was higher than both preoperative and control rates (P = 0.005 and P = 0.0002 respectively). The preoperative ratio of 2,3-dinor-TXB2 to 2,3-dinor-6-oxo-PGF1 alpha excretion was greater than that of the control group (3.2(0.8) v 1.3(0.22) in controls, (P = 0.005)), decreased significantly after operation to 0.9(0.13) (P = 0.016), and changed little, to 0.7(0.12), before discharge. The last two ratios were similar to those in normal children and significantly lower than those before operation (P = 0.004). CONCLUSION--In children with a left to right shunt the ratio of the excretion rates of the metabolites of TXA2 and PGI2 was abnormal before operation, which favoured vasoconstriction and platelet aggregation, but had decreased at discharge from hospital. The increase in excretion of PGI2 metabolites over TXA2 metabolite after intracardiac repair augurs well for pulmonary vascular recovery. [ABSTRACT FROM PUBLISHER]

OBJECTIVE--To evaluate whether circulating endothelin, a peptide that is thought to play a part in mediating vascular tone, might be high in pulmonary hypertensive congenital heart disease. DESIGN--A prospective study with a radioimmunoassay technique to estimate urinary and plasma endothelin concentrations. SETTING--A supraregional referral centre for patients with congenital heart disease. PATIENTS--The 12 hour urinary endothelin concentration in young children with an increased pulmonary blood flow (n = 24, median age eight months) were compared with those in children with right ventricular outflow tract obstruction (n = 14, median age 1.5 years) and with those in healthy controls (n = 16, median age 1.8 years). The concentrations were also measured in adolescents with irreversible pulmonary vascular disease (n = 17, median age 18 years) and compared with those in controls of similar age (n = 19, median age 18.5 years). Also the plasma concentrations in the left atrium and pulmonary artery were measured in young children with either high (n = 11, median age 10.8 months) or low (n = 5, median age 1.0 year) pulmonary blood flow, in the peripheral arterial and venous blood of young children with either high (n = 13, median age 10.8 months) or low (n = 6 median age 1.9 years) pulmonary blood flow, and in the peripheral venous blood of seven healthy young children (median age 1.7 years). RESULTS--The urinary excretion of endothelin was similar in young children of a similar age, whether they had high, low, or normal pulmonary blood flow. Also, urinary endothelin excretion in older patients with irreversible pulmonary vascular disease was similar to that in normal subjects of similar age. Urinary endothelin excretion in normal young children, however, was significantly greater than that in normal older subjects (p = 0.0001). There was no transpulmonary or arteriovenous difference detected in either children with high or low pulmonary blood flow, and plasma concentrations sampled from the left atrium, pulmonary artery, and systemic artery and vein were similar in both groups. CONCLUSION--There was no evidence to implicate circulating endothelin in the pathogenesis of pulmonary vascular disease. [ABSTRACT FROM PUBLISHER]

BACKGROUND--Children with cyanotic congenital heart disease and pulmonary outflow tract obstruction have shortened platelet survival times and are susceptible to thrombosis and organ infarction. Thromboxane A2 and prostacyclin have opposing actions on platelet aggregability and an imbalance in their biosynthesis might contribute to the pathophysiology of these complications. METHODS--Biosynthesis of thromboxane A2 and prostacyclin was investigated in 16 children (4-32 months, median 18 months) with cyanotic congenital heart disease and pulmonary outflow tract obstruction and compared with 16 healthy children of a similar age (6-34 months, median 24 months). Urinary excretion of 2,3-dinor-thromboxane B2 (a metabolite of thromboxane A2) and of 2,3-dinor-6-oxo-prostaglandin F1 alpha (a metabolite of prostacyclin) was measured. RESULTS--The children with cyanotic congenital heart disease and pulmonary outflow tract obstruction excreted more 2,3-dinor-thromboxane B2 than the healthy children: 916(163) compared with 592(122) ng/g creatinine (mean(SEM); 2p = 0.014). The ratio of excretion of 2,3-dinor-thromboxane B2 to 2,3-dinor-prostaglandin F1 alpha was greater in the patients than in the healthy control group (2.38(0.28) v 1.3(0.22)) (2p = 0.002). CONCLUSION--The balance between biosynthesis of prostacyclin and of thromboxane A2 is abnormal in children with cyanotic congenital heart disease and pulmonary outflow tract obstruction and favours platelet aggregation and vasoconstriction. [ABSTRACT FROM PUBLISHER]