| Background The ductus arteriosus (DA) serves to divert ventricular output away from the lungs and toward the placenta in utero by connecting the main pulmonary artery to the descending aorta. A persistently patent ductus arteriosus (PDA) in preterm infants is one of the common congenital heart disease. Postnatal ductal closure is regulated by exposure to oxygen and vasodilators; the ensuing vascular responses, mediated by potassium channels, voltage-gated calcium channels, mitochondrial-derived reactive oxygen species, and endothelin1, depend on gestational age. Platelets are recruited to the luminal aspect of the DA during closure and probably promote thrombotic sealing of the constricted DA. The incidence of PDA in term infants has been estimated to be57per100000live births, whereas45%preterm infant with a birth weight (BW)<1750g can be expected to have a persistent PDA. HsPDA, PDA with significant left to right shunt, in preterm infants increases morbidity and mortality. Furthermore, preterm infants who have been described to have a symptomatic PDA that ultimately leads to medical treatment. The prophylactic strategy, giving cyclo-oxygenase inhibitor to all preterm newborn babies within the first24hours after birth irrespective of the status of the ductus, has been shown to decrease the need for surgical ligation and subsequent frequency of severe intraventricular haemorrhage. Surgical ligation is performed for PDA closure when treatment with COX inhibitors is contraindicated or fails. The natural history of a PDA in premature infants cared for in today’s NICUs remains unknown. Currently, it is unclear whether and when a conservative, pharmacologic or surgical approach for PDA closure may be advantageous.Furthermore, it is unknown if prophylactic and/or symptomatic PDA therapy will cause substantive improvements in outcome. This study was designed to determine which factors was the main risk factors associated with PDA in the area and to determine the relationship between HsPDA and myocardial dysfunction, risk of chronic lung disease (CLD), pulmonary haemorrhage, intraventricular haemorrhage (IVH), necrotizing enterocolitis (NEC), renal insufficiency, retinopathy of prematurity (ROP), or death. To compare variables associated with surgical ligation or medical treatment with ibuprofen of hsPDA on neonatal echocardiographic markers, biomarkers and mortality in preterm infants with a symptomatic PDA. We sought to define the variables associated with hospital outcome in preterm infants with patent ductus arteriosus (PDA) and identify objective and reliable criteria for the prediction of PDA complications and the need for timely interverntion.Methods We conducted a single-centre, retrospective, observational study of1440premature babies, from July2010to July2011, hospitalized in NICU of the Eight One Affiliated Children’s Hospital of General Hospital of Beijing Military Region. Taking of samples compared between266/516who discharged with a PDA was defined by echocardiographic and/or clinical criteria(Gestational age31.4±2.2w, Birth weight1.74±0.60k), and250/516who without a PDA was defined by echocardiographic (Gestational age32.3±1.8w, Birth weight1.83±0.42k), for identifying their risk factors and complications. Data were analyzed with a simple and logistic regression model. Among266infants, who were diagnosed with a PDA, which matched pair study,42(of266) were treated either surgically or medically,104(Of266) were ibuprofen prophylactic treatment (to be started in the first24hours of life),59(of266) were ibuprofen symptomatic treatment (typically between2and7days after birth), and50(0f266) were treated both ibuprofen prophylactic and symptomatic treatment,20(of266) underwent surgical ligation after ibuprofen treatment failure. We retrospectively studied21infants who underwent surgical closure of ductus arteriosus, with ductus arteriosus diameter is2.74±0.48mm five infants with pneumorrhagia (23.8%), three with pneumothorax (24.2%), only1(4.76%) underwent surgical ligation directly and others were ibuprofen treatment failure. Before PDA close and after PDA close criteria, preoperative and postoperative criteria were compared between the two groups (ie, gestational age, birth weight, hemodynamic, ventilatory, biomarkers, and echographic [left atrial-aortic root ratio, mean velocity in the left pulmonary artery] parameters). Statistical analysis was performed using χ3or t test for difference of proportions, and the Mann-Whitney U test to compare the two groups. Results are expressed as median and range. P values <0.05were considered significant. All data was analyzed via SPSS16.0.Results In this study, single factor analysis show that PDA in preterm infants was significantly associated with gestational age(OR=3.427), birth weight (OR=2.539), polyembryony(OR=0.585), antenatal magnesium sulfate/Anpo (OR=1.107/2.809/19.154), gestational hypertension (OR=0.614), fetal distress (OR=2.455), placenta/amniotic fluid/umbilical cord(OR=1.894/1.782/1.800), birth asphyxia(OR=1.160).temporary hypothyroidism (OR=3.108), infection (OR=1.790), metabolic acidosis (OR=1.719), NRDS (OR=1.682), spesis (OR=0.274), use PS (OR=2.115), oxygen inhalation (OR=0.898). And blood platelet count, lower prealbumin(P<0.05) associated with PDA. A hsPDA will cause ICH, CLD, delaying gastrointestinal feed (OR=0.968), and escalating ventilatory support.The logistic regression analysis showed that antenatal magnesium sulfate (OR=0.247), infection (OR=0.589) and, small gestational age (OR=0.8868) were main risk factors for PDA in preterm infants, while oxygen inhalation was protective factor (OR=1.114). Paired Student t test and chi-square tests were used to compare demographic and hemodynamic parameters before and after ligation or ibuprofen treatment, as appropriate. In this small cohort of infants with PDA at the time PDA closure was common, occurring in the majority of infants, and usually occurring within9days after birth. There were no significant differences between before and after ibuprofen treatment in left atrium/aortic sinus and pulmonary artery diameter, but there were significantly differences in mean velocity in the pulmonary artery and left ventricle diameter. Furthermore there were significant differences in infection, hyoxemia, metabolic acidosis, feed intolerance, temporary hypothyroidism, blood platelet count, lower prealbumin, blood calcium and hematocri packed red cell volume(p<0.05). In the small cohort of21infants with PDAs shown that there was signigicant differences between before and after ligation PDA in left ventricle diameter, associated with left atrium/aortic root ratio, but has no differences.Conclusion In the area, multiple factors contribute to PDA. Small gestational age, low birth weight, antenatal magnesium sulfate/Anpo, gestational hypertension, temporary hypothyroidism,and lower prealbumin are main risk factors for PDA in preterm infants, while oxygen inhalation are protective factors. ICH, ROP, extending Length of Stay, and delaying gastrointestinal feed were main complications of hsPDA in preterm infants. The time PDA closure is usually occurring within9days after birth. When DA diameter≥2.4±0.55mm, mean velocity in the pulmonary artery≤73.31±17.0mm/s, left ventricle diameter≥11.98±1.86cm (according to color Doppler), with infection, hyoxemia, low blood platelet count, lower prealbumin, temporary hypothyroidism, and metabolic acidosis, we advise prophylactic ibuprofen treatment is performed for PDA closure. In order to avoid inappropriate ibuprofen treatment for PDA, when DA diameter≤2.26±0.47mm, with no clinical features of PDA and pulmonary disease, spontaneous closure may occur in most infants. Surgical ligation is associatied with which DA diameter≥2.74±0.48mm, left atrium/aortic sinus ratio≥1.33±0.18. But larger comparative studies are needed to validate these findings. Surgical ligation is considered in those, as mentioned above, with temporary hypothyroidism, lower total protein, hematocri packed red cell volume or who fail to respond to medical treatment. |
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