Discussion

To our knowledge, this is the first meta-analysis comparing percutaneous transcatheter for patent ductus arteriosus closure with surgical ligation. Transcatheter percutaneous closure was associated with reduced all-cause mortality and lower haemodynamic instability. In addition, we discovered that transcatheter percutaneous closure protected against retinopathy of prematurity and periventricular leukomalacia.

There was no significant difference in bronchopulmonary dysplasia, severe complications, and related morbidities such as necrotising enterocolitis and intraventricular haemorrhage between groups. Despite the differences in group size, the more stringent inclusion criteria (preterm birth, weighing less than 2,500 g) allowed both groups to be reasonably homogeneous and comparable (see Table 1).

Different publications define post-ligation syndrome differently based on clinical evaluations, therapies, and echocardiographic findings. For example, the Tennessee group considers post-ligation syndrome clinically significant if four of seven criteria are met during the first 24 hours after the procedure: a) a peak inotrope score of >15, b) a ten mmHg decrease in mean blood pressure from baseline, c) evidence for new-onset pulmonary venous congestion chest X-ray, d) a 30% increase in respiratory severity score, e) a 20% absolute decrease in ejection fraction, f) left ventricular output 200 ml/kg/min, and g) a >20% decrease in tissue Doppler-derived lateral and medial E’). ^{Reference Philip, Waller and Chilakala17} To simplify the definition and analysis process, we describe post-ligation syndrome as hypotension requiring inotropic support and failure of oxygenation and ventilation, which may occur 6–12 hours following ligation due to left ventricular systolic and diastolic failure, respectively. This decompensation is primarily driven by increased afterload. ^{Reference Giesinger, Bischoff and McNamara18}

The definition of a haemodynamically unstable patent ductus arteriosus needs to be clarified, and there is no consensus. ^{Reference Lee19} Currently, most doctors decide to intervene based on clinical evidence and echocardiographic criteria to define a haemodynamically significant ductus arteriosus better. ^{Reference McNamara and Sehgal20} However, there is variation between groups regarding the specific criteria. In this review, most articles consider a ductus arteriosus to be haemodynamically unstable when it is larger than 2 mm, with criteria of haemodynamic instability, such as using vasoactive drugs.

Pulmonary congestion and low systemic circulation, in the context of a patent ductus arteriosus, can lead to compromised perfusion to the bowel, kidney, and brain. This pathophysiology justifies prolonged assisted ventilation, higher mortality rates, bronchopulmonary dysplasia, necrotising enterocolitis, impaired renal function, intraventricular haemorrhage, periventricular leukomalacia, and cerebral palsy. ^{Reference Mitra, Scrivens, Von Kursell and Disher21}

We found no difference in the outcome of major complications. However, there was less retinopathy and leukomalacia in the transcatheter percutaneous closure group. This result is likely due to the need for greater haemodynamic changes associated with surgery. Importantly, with technological advancements, complications of device transcatheter percutaneous closure implantation can now be minimised, particularly in extremely low-birth-weight infants. New implant techniques have been developed to reduce device malposition or protrusion in this population. ^{Reference Sathanandam, Gutfinger and Morray22} However, it is important to interpret our findings cautiously as evaluating comorbidities was not our primary objective.

The optimal timing for closing the ductus arteriosus remains a subject of ongoing debate. Acting promptly correlates with a reduced likelihood of associated health complications. ^{Reference Bischoff, Kennedy and Backes23} Historically, catheterisation for ductal closure was reserved for more severe clinical scenarios, often arising from delayed closure (beyond 15 days). With the FDA’s approval of the innovative “Amplatzer Piccolo Occluder” device, extending its use to premature infants weighing >700 g, recent investigations have suggested that early closure may be a viable option, given the risks of comorbidities associated with delayed closure. ^{Reference Regan, Benbrik and Sharma24}

Recent studies indicate that early closure is considered safe and may be a preferred option for preterm babies with low birth weight. ^{Reference Barry, Gudausky and Balzer25} These contemporary insights propose that initiating treatment before the duct becomes clinically significant may prevent damage to surrounding tissues. Furthermore, this approach may reduce reliance on nonsteroidal anti-inflammatory drugs, minimise associated side effects, and contribute to shorter hospital stays – a proposition consistent with earlier findings highlighted in a Cochrane review. ^{Reference Mitra, Scrivens, Von Kursell and Disher21}

This study has limitations. We faced challenges evaluating respiratory impairment due to a lack of standardisation. ^{Reference Sathanandam, Gutfinger and Morray22,Reference Wei, Chen and Lin26–Reference Philip, Waller and Chilakala30} It was not possible to assess ventilation time as an outcome due to insufficient data. We only used observational studies, which are prone to confounding factors. Multivariable adjusted analyses in the individual studies to correct for severity of clinical presentation were not performed. Of note, confounding by illness severity would most likely favour the surgical group, if present. In other words, if more severe patients are excluded from the surgical group, this would typically lead to worsened outcomes among the sicker population of the transcatheter group. Nevertheless, we observed the opposite result, increasing the confidence in the findings. Finally, although most papers used clinical and echocardiographic parameters to determine which ductus arteriosus was haemodynamically significant, no definitive and uniform diagnostic criteria existed. Similarly, the criteria for respiratory impairment and the definition of post-ligation syndrome varied between different studies. Future research may benefit from the standardisation of outcome definitions.