Relationship of Patent Ductus Arteriosus Size to Echocardiographic Markers of Shunt Volume

The definition of a hemodynamically significant ductus arteriosus

“…There is an increasing realization that an accurate estimation of shunt volume, rather than intermittent and discreet measurements of ductal diameter, provides a more holistic assessment of the hemodynamic impact of a PDA. 7 Flow across the PDA is governed by Poiseuille's Law which states that: "At a constant driving pressure [the pressure gradients across the PDA], the flow rate of liquid through a tube is directly proportional to the fourth power of the radius of the tube and inversely proportional to the length of the tube and viscosity of the fluid. 8 " In the setting of a PDA, the pressure gradients across the vessel, the length and diameter of the PDA and blood viscosity all constantly change over the first few days following birth.…”

“…10 Although there are important considerations with each marker (e.g., pseudonormalization of some indices from offloading of the left atrium with a patent foramen ovale or atrial septal defect), 11 recent evidence has demonstrated no difference between the measures in the presence of a large (>2 mm) atrial level shunt. 7 Myocardial function is another important component of hemodynamic significance, but has often been forgotten in the assessment of a PDA and warrants further attention. Although much of the morbidity and mortality is related to the effects of the PDA on the systemic and pulmonary circulations, cardiac function is still an important driver in disease.…”

Ibuprofen treatment after the first days of life in preterm neonates with patent ductus arteriosus

“…The echocardiographic parameters to define significance of the PDA have limitations. No details on the systemic hypoperfusion, such as flow in the arteria mesenterica superior or descending aortae were used [28]. Van Laere et al also suggest that more echocardiographic parameters should be used for interpreting the hemodynamic significance of a PDA [29].…”

Pulmonary hypertension is an important co‐morbidity in developmental lung diseases of infancy: Bronchopulmonary dysplasia and congenital diaphragmatic hernia

“…As such, cardiac catheterization should be considered as a second line of evaluation to establish the diagnosis of PH, evaluate the burden of lung disease and its effect on pulmonary arterial pressures, assess the vasculature (including pulmonary veins), characterize intracardiac shunts and the associated net pulmonary circulatory load, perform acute vasoreactivity testing and assess for changes in left heart diastolic function 1,31,42,68‐73 . To optimize risk and benefit ratio, catheterization may be most helpful in the child whose burden of disease seems disproportionate to degree of developmental lung disease.…”