Pulmonary Artery Hypoplasia in Neonates With Tetralogy of Fallot

BACKGROUND Neonates with symptomatic tetralogy of Fallot (sTOF) with hypoplastic pulmonary arteries (hPA) are considered high risk. Data are needed to inform the impact of hPA on outcomes, and the ideal management strategy. OBJECTIVES 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. METHODS Neonates with sTOF from 2005 to 2017 were reviewed from the Congenital Cardiac Research Collaborative. Criteria for hPA included a unilateral PA z score <-2.0 and contralateral PA z score <0. Primary outcome was mortality. Secondary outcomes included reintervention and PA growth. RESULTS We included 542 neonates with sTOF, including 188 (35%) with hPA and 354 (65%) with normal PA, with median follow-up of 4.1 years. 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. Staged repair (vs primary TOF repair) was less common in the hPA cohort (36 vs 44%; P = 0.07). Survival was similar between groups (unadjusted P = 0.16; adjusted P = 0.25). Reintervention was more common in the hPA group (HR: 1.28; 95% 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). PA growth at 1 year was greater in the hPA cohort, particularly for the right PA (P < 0.001). CONCLUSIONS Despite perception, the presence of hPA in neonates with sTOF conferred no increase in overall hazard of mortality or reintervention after definitive repair. PA growth was superior in the hPA cohort. These findings suggest that the presence of hPA does not adversely impact outcomes in sTOF. (J Am Coll Cardiol 2023;82:615-627) (c) 2023 by the American College of Cardiology Foundation.