MANAGEMENT STRATEGIES OF PATENT DUCTUS ARTERIOSUS IN PRETERM INFANTSREVIEW ARTICLE

Patent ductus arteriosus (PDA) is a frequent congenital heart defect. It becomes even more common in preterm infants with a high burden of consequences and adverse effects. Recently, the emergence of a constellation of different management protocols urged for a comprehensive summery of the best evidence-based interventions. A detailed electronic search for evidence was carried out, including Cochrane, systemic and narrative reviews. Variable controversial aspects of PDA diagnosis and management were discussed. Brief echocardiographic and laboratory PDA diagnosis followed by a review of symptomatic and asymptomatic PDA Surgical and nonsurgical management strategies included. Early interventionfor asymptomatic PDA depending on echo scoring, and grading all symptomatic PDAs clinically and echographically can guide management and decrease the need for surgical ligation.


238
Paracetamol is as effective, at doses of especially in late PDA after the second week. As well as, it may decrease the need for surgical ligation. [21] In a recent Cochrane review, Paracetamol showed similar response to Indomethacin and Ibuprofen with fewer adverse effects. [22] Timing of treatment: Therapy could be started prophylactically to all high-risk infants, therapeutically to asymptomatic HsPDA cases, diagnosed after screening echocardiography, therapeutically to symptomatic high-risk cases, or late after deterioration. Evidence for the best time to start treatment is still far from clear.
Prophylactic Indomethacin decreases the risk of HSPDA, the need for surgical ligation, severe IVH, and significant pulmonary hemorrhage. [23] Better Long-term outcome including decreases BPD and death was shown in a prospective double cohort-controlled study by Liebowitz. [24] However, no significant improvement in death, BPD, or severe neurosensory impairment could be replicated in other studies. [23,25] Similarly, prophylactic Ibuprofen reduces significant PDA and the requirement for surgical ligation but without considerable differences in mortality, BPD, IVH, [26] or NEC. [27] Additionally, early rescue treatment did not result in any difference in mortality, BPD, or days on oxygen. [28] Although early indomethacin treatment increases PDA closure rate, it is associated with higher renal adverse effects and more severe complications without respiratory benefit over the delayed administration. [29] Furthermore, PDA has a high tendency for spontaneous closure, and medical treatment is fraught with serious side effects.
Conversely, delaying treatment decreases the response rate; as when the ductal tissue matures, it becomes less dependent on prostaglandins [30] and exposes the baby to the hemodynamic effects of the PDA in the early critical period of life. Additionally, Van Overmeire's study [29] is relatively old, less powered to detect the BPD difference (total recruited only 127cases), with probably more severe cases in the early treatment arm (higher LA/Ao).
The best available balance between these contradictory pieces of evidence could come from the grading system invented by McNamara and Sehgal [31] based on clinical severity and echocardiographic significance. It is a reasonable grading system, although it needs more studies to demonstrate its effects on treatment or outcome.
Alternatively, early echocardiographic screening for PDA with a targeted treatment for infants at a high risk of spontaneous early ductal constriction failure has been associated with reduced mortality and pulmonary hemorrhage. [32] El Khuffash et al. [33] suggested early PDA screening at the age of 2 days with severity scoring that can predict adverse outcomes such as BPD and death. Additionally, screening could limit the number of infants exposed to unnecessary PDA prophylaxis.
The best practice is to do echo screening for infants less than 28 weeks' gestation at the age of 2 days then following El Khuffash et al. severity scoring for the treatment decision. [21] However, all symptomatic PDAs should be echoed to confirm HsPDA and to exclude duct dependent congenital heart diseases. Management decision is taken according to the gestational age, hemodynamic state, and echocardiographic findings guided by McNamara and Sehgal's grading system. [31] However, if the first Ibuprofen course is not effective, Repeated courses are equally potent in decreasing the rate of treatment failure and the need for surgical ligation. [34] Surgical treatment: Surgical PDA ligation is considered for neonates who are persistently symptomatic after failure or contraindication to noninvasive treatment. [35] It is generally reserved for infants who are dependent on mechanical ventilation or with congestive heart failure. However, it could be performed either early on all PDAs that fail to close after pharmacologic therapy, or later only after cardiopulmonary compromise develops. [36] The Selective late ligation approach resulted in the same incidence of BPD, ROP, sepsis, and neurologic insult with a significantly lower NEC rate [36] and lower incidence of abnormal Neurodevelopmental outcomes. [37] Hence, we follow selective ligation for the patient who remains on high ventilator settings or stays significantly symptomatic after failure or contraindication to medical therapy. This approach is less invasive, decreases the cost of early ligation, the burden of perioperative care, and the serious complications of PDA ligation.

239
Surgical ligation is effective for rapid and completeductal closure without significant increase in mortality during hospitalization compared to pharmacological closure. [38] However, serious complications are not uncommon. Namely, postoperative severe hemodynamic and respiratory collapse (post ligation collapse syndrome PLCS) which is the most serious complication that follows surgical ligation [39] and other complications including; pneumothorax, left vocal cord paralysis, lymphatic leak, injury to the left phrenic nerve, [40] chylothorax, [41] and scoliosis. [42] On the Long term, surgical ligation is associated with a higher risk of BPD, [43,44] retinopathy of prematurity, [45] and neurodevelopmental impairment. [37,45 ,46] Therefore, extensive postoperative care and monitoring are needed. Cardiovascular support with volume and inotropic agents to achieve adequate blood pressure and perfusion is important to preserve postoperative infant stability. [47] Tashiro et al. [48] have run a large study of 63,208 patients with PDA. Of these, surgical ligation was carried out in 6766 (10.7%). This ratio varies according to gestational age from 37% of fewer than 24 weeks to 12.5% for 27-28 weeks' infants.

Conclusion:-
In conclusion, PDA is common in preterm infants. Nevertheless, not all PDAs require treatment. Early management of asymptomatic cases, depending on echo scoring, then echoing all symptomatic PDAs and grading them clinically and echocardiographically can guide treatment and cutback the number of cases who required surgical ligation. Infants who have a cardiopulmonary compromise should be referred for surgical ligation if not responding to medical therapy after the second course or if there is a contraindication to medical therapy. References:-