Lung function in very low birth weight infants after pharmacological and surgical treatment of patent ductus arteriosus - a retrospective analysis

BACKGROUND The indications and strategies for treatment of patent ductus arteriosus (PDA) are controversial, and the safety and long-term benefits of surgical PDA closure remain uncertain. The aim of this study was to compare the lung function of very low birth weight (VLBW) infants after successful PDA treatment with a cyclooxygenase inhibitor or secondary surgical ligation. METHODS A total of 114 VLBW infants (birth weight < 1500 g), including 94 infants (82%) with a birth weight < 1000 g, who received treatment for hemodynamically significant PDA (hsPDA), were examined at a median postmenstrual age of 48 weeks. All infants were initially given pharmacological treatment, and 40 infants (35%) required PDA ligation. Lung function testing (LFT) included tidal breathing measurements, measurement of respiratory mechanics assessed by the occlusion test, whole-body plethysmography, SF6 multiple breath washout, forced expiratory flow (V'maxFRC) by the rapid thoracoabdominal compression technique, exhaled NO (FeNO), and arterialized capillary blood gas analysis. RESULTS On the day of the LFT, the 2 groups had similar postconceptional age and body weight. However, the PDA ligation group was more immature at birth (p < 0.001) and had reduced respiratory compliance (p < 0.001), lower V'maxFRC (p = 0.006), increased airway resistance (Raw) (p < 0.001), and impaired blood gases (p < 0.001). Multivariate analysis showed that PDA surgery was an independent risk factor for increased Raw. CONCLUSION PDA ligation after failed pharmacological treatment is associated with impaired lung function as compared to successful pharmacological closure in infants at a postmenstrual age of 48 weeks. However, only Raw was independently affected by PDA ligation, while all other differences were merely explained by patient characteristics.