Preterm patent ductus arteriosus: are we any closer to knowing when to treat?

Debate about the importance of the preterm patent ductus arteriosus (PDA) remains unresolved. Ultrasound studies of PDA have suggested that the haemodynamic impact may be much earlier after birth than previously thought but we still don't know when to treat a PDA. Studies that have tested symptomatic or pre-symptomatic treatment are mainly historical and have not tested the effect of no treatment. Prophylactic treatment is the best studied regimen but improvements in some short term outcomes do not translate to any difference in longer term outcomes. Neonatologists have been reluctant to engage in trials which test treatment against almost never treating. Observations of very early postnatal haemodynamic significance suggest targeting treatment on the basis of the early postnatal constrictive response of the duct may optimize benefits. A pilot trial of this strategy showed reduction in the incidence of pulmonary haemorrhage but more trials of this strategy are needed.