Ratio of patent ductus arteriosus resistant to medical treatment and affecting factors in preterms

Introduction and Aim: Ductus arteriosus (DA) is the vascular connection between the main pulmonary artery and the aorta during the fetal period which carries blood away from the pulmonary bed. Patent ductus arteriosus (PDA) is when the DA remains open for longer than expected after birth. PDA is the most common cardiovascular condition affecting premature newborns. In order to prevent complications of PDA, it is estimated that 10-34% of babies born before the 32 weeks of gestation and 61% of babies born before the 28 weeks of gestation receive medical and/or surgical treatment. In some newborns who receive medical treatment for PDA, ductal patency may continue despite treatment. Although there are few studies on the factors that cause resistance to medical treatment of PDA in newborns, gestational age (GA), birth weight, and PDA diameter size are generally the prominent factors. This study aimed to examine the PDA closure rate and the factors affecting medical treatment resistancy in severely preterm patients with a single course of medical treatment. Materials and Methods: Our study, which we planned as a single-center retrospective descriptive cross-sectional study, was carried out through the file records of severely premature babies under 32 GA and their mothers who were followed up at Akdeniz University Hospital between May 2017 and May 2022. The study group was divided into two groups: treatment-responsive group and treatment-resistant group. The groups were compared in terms of demographic, clinical, laboratory and echocardiographic (ECHO) data. Parameters that showed significant differences in univariate analysis were evaluated by multivariate logistic regression analysis. Results: The cases average GA was determined as 27.1 ± 2.24, and the average birth weight was determined as 1026 ± 338g. Histological chorioamnionitis was detected in 20 (24.3%) of the cases mothers' placenta, in the antenatal period clinical chorioamnionitis was detected in 2 (2.4%), and premature rupture of membranes (PROM) was detected in 16 (19.5%) mothers of the cases. The first course of PDA closure treatment was applied to all patients included in the study and closure was observed in 55 (66%) of the patients with a single course of treatment. When compared in terms of demographic data, the presence of chorioamnionitis and PROM history was found to be significantly higher in the treatment-resistant group (p:0.004, p:0.027). GA was observed to be significantly lower in the treatment-resistant group (p:0.002). When compared in terms of clinical data, the incidence of bronchopulmonary dysplasia (BPD), invasive, noninvasive, total respiratory support durations and length of hospital stay were found to be higher in the medical treatment-resistant group (p:0.01, p:0.03, p:0.037, p:0.012, p:0.014 respectively). When compared in terms of ECHO findings, duct diameter width and PDA diameter index were found to be significantly higher in the treatment-resistant group (p:0.030, p:0.008). When comparing the treatment start times, the medical agent used and the application method of the agents no statistically significant difference was detected between the groups. When the patients were evaluated by comparing laboratory findings in terms of both treatment resistance and the need for surgical ligation, no statistically significant difference was detected. In univariate logistic regression analysis it was observed that the GA, chorioamnionitis, PROM, PDA diameter width, PDA diameter index, and the average of the first 3-day urine output were variables affecting the resistance to medical treatment. Among these, GA (OR 0.76 95% CI 0.58- 0.99, p:0.048) and PDA diameter width (OR 3.55 95% CI 1.26- 10.01, p:0.016) were determined as independent factors associated with medical treatment resistance in multivariate logistic regression analysis. Conclusion: Non-responsiveness to treatment was detected in 34% of the cases with the first course of treatment, which is similar to the literature. It was found that the most important factors affecting treatment response were PDA diameter width and GA. Other factors affecting treatment response were the presence of chorioamnionitis and the presence of PROM. Keywords: Prematurity, Gestational age, Ductus arteriosus, Patent ductus arteriosus, Chorioamnionitis, Early rupture of membranes, Bronchopulmonary dysplasia