**7. Established techniques for closure**

Treatment options are continuously evolving [25], and have included routine pharmacological treatment, conservative management, surgical ligation and transcatheter closure (**Table 2**). While indications for closure are not fully agreed upon, certain contraindications are noted below:


#### **7.1 Medical therapy**

Pharmacological treatment with COX inhibitors is usually the initial treatment for PDA. Currently, pharmacological therapy consists of intravenous or oral


#### **Table 2.**

*Advantages and disadvantages of therapies.*

indomethacin, ibuprofen, or acetaminophen in varying dosages. The two most common options are intravenous standard doses of indomethacin and ibuprofen. In 2018, a meta-analysis of 68 RCT of 4802 infants found that among all preterm infants <37 weeks gestation, the overall PDA closure rate with one of the above treatment modalities was 67%. Oral ibuprofen was the most effective treatment, and none of the treatments increased the risk of mortality, NEC, or IVH compared to placebo or no treatment controls [25]. Slower absorption rates and a longer half-life of oral ibuprofen may increase the time of contact with the PDA, possibly explaining its improved effectiveness over intravenous routes [25]. The effectiveness of medical therapy is at best 50–70% and lower for those <32 weeks gestation [24–26].

Conservative management without the use of pharmacotherapeutics has become a recent trend in management of the PDA [16, 22]. Because many preterm infants will spontaneously close the ductus within the first week, early routine treatment with pharmacological therapy may not offer any benefit. Targeted therapy towards hsPDA based on clinical and echocardiographic thresholds is becoming the standard of care.
