Dor Markush, MD; Myriam Almeida-Jones, MD; Aneela R. Reddy, MD; Jennifer Chang, MA; Evan M. Zahn, MD
Introduction
In term or late preterm infants, closure of the ductus arteriosus often occurs spontaneously in the first few days of life.[1] However, this process of ductal constriction is generally delayed in premature infants, especially those with Extremely Low Birth Weight (ELBW). 50-70% of infants born at < 28 weeks gestational age (GA) have a moderate-to-large Patent Ductus Arteriosus (PDA) that persists weeks after birth.[2] Incidence tends to correlate inversely with birth-weight and gestational age.[3] A hemodynamically-significant PDA results in a large left-to-right shunt and aortic diastolic runoff, contributing to pulmonary congestion, Respiratory Distress Syndrome, prolonged assisted ventilation, increased risk of necrotizing enterocolitis, renal insufficiency, intraventricular hemorrhage, and an overall increased risk for morbidity and mortality particularly in ELBW patients.[4-7]
Management of a clinically-significant PDA in ELBW neonates includes: fluid restriction, pharmacotherapy, surgical ligation and, more recently, transcatheter device closure. Up to half of all ELBW babies born prior to 28 weeks gestation require medical or surgical treatment for their PDA.[8]
FIGURE 1 Abbott PiccoloTM Device (formerly ADO II-AS). A self-expending wire mesh device that is shorter and softer compared to its predecessors. Its smaller central waist and slightly-larger retention disks facilitate complete intraductal deployment, which is desirable in the premature Patent Ductus Arteriosus, so as to minimize protrusion into surrounding structures such as the left pulmonary artery and descending aorta. Photograph: Abbott Laboratories.
Medical management with non-selective cyclooxygenase inhibitors such as Indomethacin or Ibuprofen in low birthweight infants has an estimated success rate of only 50-60% and may result in complications such as impaired renal function and intestinal perforation.[9,10] When medical therapy is unsuccessful, patients may be referred for surgical ligation, or a continued conservative approach of observation and medical management is undertaken. Surgical ligation, while technically successful, is invasive in nature and typically performed through a limited left thoracotomy. Ligation has also been associated with significant perioperative complications, including pneumothorax, bleeding, wound infection, phrenic nerve palsy, vocal cord paralysis,[11-13] and possible neurodevelopmental impairment.[14] Thus, in the current era, surgical ligation is often avoided in ELBW neonates.
Transcatheter PDA closure has emerged as a viable option for these neonates over the last several years. Previously, a catheter-based option for PDA closure was not widely available for these small infants secondary to concerns related to vascular access, patient fragility, contrast administration, and lack of devices specifically suited for this unique and fragile population. In recent years, a number of groups have reported successful transcatheter PDA closure in ELBW neonates using various devices – including coils,[15] Amplatzer Vascular Plug II,[16] Medtronic Micro-Vascular Plug,[17] Amplatzer Ductal Occluder II,[18] and, most recently, the Amplatzer Ductal Occluder II Additional Sizes (ADO II-AS) device.[19]
To read the full article, please go to the September 2019 Issue of CCT.