Despite perception, the presence of hypoplastic pulmonary arteries (hPA) does not adversely impact outcomes in neonates with symptomatic tetralogy of Fallot (sTOF), new data suggest. The study, published online Monday and in the Aug. 15 issue of the Journal of the American College of Cardiology, noted that neonates with tetralogy of Fallot who are symptomatic due to cyanosis require early intervention, which can take the form of staged repair (SR), whereby initial palliation (IP) is followed by later complete repair (CR), or operative primary repair (PR). The research team, led by Christopher J. Petit, MD, from the NewYork-Presbyterian Morgan Stanley Children’s Hospital, New York, and the Emory University School of Medicine, Atlanta, noted that the selection of management strategy in sTOF may be affected by consideration of patient characteristics, center or operator preferences, or perceived superiority in outcomes. However, they also noted that hPA is frequently found in neonates with sTOF: “Given perceived adverse impact of hPA on surgical technique and clinical outcomes, the presence of hPA may alter management strategy for the sTOF neonate,” they said. “However, the basis for these perceived inferior outcomes is opaque, and data suggesting poor outcomes are intermixed with TOF populations with major aortopulmonary collateral arteries (MAPCAs),” they said, noting that more common manifestations of hPA have been less well-studied and remain a source of debate within the congenital heart disease community. “This is among the largest reported cohort of sTOF neonates requiring early intervention, and the first to examine the impact of hPA on clinically meaningful outcomes,” said the team. “After adjustment, we found that the presence of hPA was not associated with a greater risk of early or overall mortality. Survival was similar in the hPA and normal PA cohorts, regardless of initial treatment strategy used.” Study setup Petit and colleagues used recently published data sets from the Congenital Cardiac Research Collaborative to assess the impact of hPA on longitudinal outcomes, including mortality and reintervention, in 542 neonates with sTOF. “The objectives of this study were to quantify the impact of hPA on outcomes in neonates with sTOF and measure the impact of strategy on pulmonary artery (PA) growth in this population,” said the team, noting that criteria for hPA included a unilateral PA z score <-2.0 and contralateral PA z score <0. The primary outcome was mortality, while secondary outcomes included reintervention and reintervention after definitive TOF repair (CR or PR), as well as hospital length of stay (LOS), intensive care unit (ICU) LOS, and durations of mechanical ventilation, inotropic agents, cardiopulmonary bypass, and inhaled anesthetic exposure. Key results The team reported that of the cohort of 542 neonates with sTOF, 188 patients (35%) met criteria for hPA, whereas 354 (65%) had normal PA dimensions, with median follow-up of 4.1 years. Overall, the hPA and normal PA cohorts had similar birth weight and gestational age; however, there was a lower incidence of TOF/PA in the hPA cohort compared with the normal PA cohort (34% vs 57.6%; P < 0.001), they said, noting that the median right and left hPA z scores were -2.19 (25th-75th percentile: -2.55 to -1.94) and -2.23 (25th-75th percentile: -2.64 to -1.91), respectively. Furthermore, staged repair (vs primary TOF repair) was less common in the hPA cohort (36% vs 44%; P = 0.07), said the team. Analysis showed that survival was similar between groups (unadjusted P = 0.16; adjusted P = 0.25), and that though reintervention was more common in the hPA group (hazard ratio [HR]: 1.28; 95% confidence interval [CI]: 1.01-1.63; P = 0.044); there was no difference after definitive repair (HR: 1.21; 95% CI: 0.93-1.58; P = 0.16). “Despite perception, the presence of hPA in neonates with sTOF conferred no increase in overall hazard of mortality or reintervention after definitive repair,” said the team, noting that PA growth was superior in the hPA cohort at 1 year – particularly for the right PA (P < 0.001). “These findings suggest that the presence of hPA does not adversely impact outcomes in sTOF,” they concluded, adding that further research is needed to assess the impact of evolving transcatheter approaches to palliation on management and outcomes in neonates with TOF and hPAs. Less guesswork: More data-driven outcomes Writing in an accompanying editorial, Barry A. Love, MD, from the Icahn School of Medicine at Mount Sinai, New York, said the new data call into question the assumptions of the 2022 American Association for Thoracic Surgery consensus statement on neonates with TOF, which said that “the presence of small pulmonary arteries is a risk factor for poor outcomes, and that alternative palliative strategies for such patients ‘is reasonable to consider’—Class IIa, LOE: B-NR.” The editorialist added that it is “encouraging” to see that both staged and primary repair strategies appeared not to differ from each other in major endpoints: “Although this was not a randomized study, the data would certainly suggest that relatively hypoplastic pulmonary arteries alone should not be a reason to opt for a staged repair,” he said. “Decision making in congenital heart disease differs from adult cardiology in that the patient anatomies vary considerably and there are often less data, allowing for more center-specific practices and ‘conventional wisdom’ to guide management rather than large randomized trials on which to base clinical decisions,” noted Love. “Studies like this one will help advance the field, making for less guesswork and more data-driven superior outcomes.” Sources: Petit CJ, Glatz AC, Goldstone AB, et al. Pulmonary Artery Hypoplasia in Neonates With Tetralogy of Fallot. J Am Coll Cardiol 2023;82:615-627. Love BA. Management of Infants With Tetralogy of Fallot: Questioning Conventional Wisdom. J Am Coll Cardiol 2023;82:628-630. Image Credit: varisa – stock.adobe.com