Noninvasive methods for determining pulmonary vascular function in children with pulmonary arterial hypertension: application of a mechanical oscillator model.

Objective: Noninvasive diagnostics for pulmonary arterial hypertension (PAH) have traditionally sought to predict main pulmonary artery pressure from qualitative or direct quantitative measures of the flow velocity pattern obtained from spectral Doppler ultrasound examination of the main pulmonary artery. A more detailed quantification of flow velocity patterns in the systemic circuit has been obtained by parameterizing the flow trace with a simple dynamic system model. Here, we investigate such a model's utility as a noninvasive predictor of total right heart afterload and right heart function.

Genetic variation in the mitochondrial enzyme carbamyl-phosphate synthetase I predisposes children to increased pulmonary artery pressure following surgical repair of congenital heart defects: a validated genetic association study.

Increased pulmonary artery pressure (PAP) can complicate the postoperative care of children undergoing surgical repair of congenital heart defects. Endogenous NO regulates PAP and is derived from arginine supplied by the urea cycle. The rate-limiting step in the urea cycle is catalyzed by a mitochondrial enzyme, carbamoyl-phosphate synthetase I (CPSI).

Noninvasive Doppler tissue measurement of pulmonary artery compliance in children with pulmonary hypertension.

Background: We have shown previously that input impedance of the pulmonary vasculature provides a comprehensive characterization of right ventricular afterload by including compliance. However, impedance-based compliance assessment requires invasive measurements. Here, we develop and validate a noninvasive method to measure pulmonary artery (PA) compliance using ultrasound color M-mode (CMM) Doppler tissue imaging (DTI).

Use of myocardial performance index in pediatric patients with idiopathic pulmonary arterial hypertension.

Background: The myocardial performance index (MPI) correlates with clinical status in adults with idiopathic pulmonary arterial (PA) hypertension (IPAH). This pediatric study used MPI to assess response to bosentan therapy.

Methods: The study included 12 children with IPAH and 12 healthy control subjects.

Congenitally Corrected Transposition of the Great Arteries: Current Treatment Options.

Congenitally corrected transposition of the great arteries is a relatively rare cardiac malformation characterized by atrioventricular and ventriculoarterial discordance. This double discordance results in a physiologically corrected circulation with the morphologic right ventricle (RV) serving as the systemic pump. Associated anomalies are present in approximately 98% of cases and include most commonly ventricular septal defect, pulmonary stenosis, and anomalies of the systemic atrioventricular valve (SAVV).

Effect of cardiopulmonary bypass on urea cycle intermediates and nitric oxide levels after congenital heart surgery.

Objective: To test the hypothesis that cardiopulmonary bypass used for repair of ventricular septal defects and atrioventricular septal defects would decrease availability of urea cycle intermediates including arginine and subsequent nitric oxide availability.

Study Design: Consecutive infants (n = 26) undergoing cardiopulmonary bypass for repair of an unrestrictive ventricular septal defect or atrioventricular septal defect were studied. Blood samples were collected immediately before surgery, immediately after surgery, and 12 hours, 24 hours, and 48 hours after surgery.