Change in Blood Pressure and Pulse Pressure in Preterm Infants After Treatment of Patent Ductus Arteriosus With Indomethacin

Background and Objectives: Patent ductus arteriosus (PDA) is associated with increased morbidity and mortality in premature infants. Therefore, an early diagnosis and treatment of a hemodynamically significant PDA are very important. A widened pulse pressure is considered to be a well known clinical sign of a PDA in older infants and children; however, whether this is also applicable in the case of preterm infants remains to be confirmed. The aims of this study were to investigate the change in blood pressure (BP) before and after medical treatment of a PDA with indomethacin and to evaluate if the change in the pulse pressure in preterm infants with a medically treated PDA could be used as a reliable clinical predictor of a hemodynamically significant PDA. Subjects and Methods: Between January 2005 and June 2009, a retrospective analysis was performed in preterm infants with a hemodynamically significant PDA (PDA group, n=72) and preterm infants without a PDA (control group, n=72) at the Chonnam National University Hospital Neonatal Intensive Care Unit. The PDA was closed by treatment with indomethacin. The BP was compared between the two groups over the seven days after the first dose of indomethacin. Results: In preterm infants with a hemodynamically significant PDA, the mean systolic (55.1${\pm}$6.0 mmHg) and diastolic BPs (31.4${\pm}$6.2 mmHg) were lower than those in the controls (mean systolic BP 58.0${\pm}$6.4 mmHg, mean diastolic BP 34.7${\pm}$6.0 mmHg) before indomethacin treatment. When the ductus arteriosus was successfully closed by indomethacin treatment, there was a gradual increase in both the systolic and diastolic BPs without any change in the pulse pressure. Conclusion: The results of this study show that a widened pulse pressure is not a useful clinical sign of a hemodynamically significant PDA in preterm infants. However, low systolic and diastolic BPs may be useful clinical signs of a hemodynamically significant PDA in preterm infants. If the systolic and diastolic BP is low, a PDA should be considered and echocardiography should be performed for early diagnosis and treatment.