Patent ductus arteriosus in preterm infants born before 30 weeks’ gestation: high rate of spontaneous closure after hospital discharge

Aim: The aim of this study was to determine the spontaneous closure rate of patent ductus arteriosus at a 2-year follow-up, following failed medical therapy and beyond initial hospital discharge, and to evaluate in-hospital spontaneous or pharmacological closure rates. Materials and methods: A retrospective evaluation was conducted in a cohort of preterm infants admitted to the Neonatal ICU of Ancona between January, 2004 and June, 2013. Inclusion criteria were gestational age between 24+0 and 29+6 weeks or birth weight <1250 g; admission within 48 hours from birth; and discharge alive from hospital. All infants received routine heart ultrasound between 48 and 72 hours of life. Haemodynamically significant patent ductus arteriosus was defined as a duct diameter >1.5 mm, a left atrium-to-aorta ratio >1.4, and/or reversal of end-diastolic flow in the aorta >30% of the anterograde. First-line treatment was intravenous ibuprofen. Intravenous indomethacin was used if ibuprofen failed. Surgical ligation was considered in haemodynamically significant patent ductus arteriosus after medical treatment. Results: A total of 593 infants met the inclusion criteria, and patent ductus arteriosus was diagnosed in 317 (53.4%). Among them, 283 (89.3%) infants had haemodynamically significant patent ductus arteriosus, with pharmacological closure achieved in 228 (80.6%) infants and surgical ligation performed in 20 (7.1%). Follow-up at 24 months was available for 39 (81.3%) of 48 infants with patent ductus arteriosus at the hospital discharge: 36 (92.3%) underwent spontaneous closure, two (5.1%) underwent surgical ligation, and one (2.6%) had a patent ductus arteriosus. Discussion: A significant number of patent ductus arteriosus that fail pharmacological closure undergo spontaneous closure by the age of 2 years. This information should be taken into account when considering surgery or additional attempts of pharmacological closure.