Abstract 14760: Right Ventricular Function in Preterm Neonates: Reference Values for Longitudinal Strain by Two-dimensional Speckle Tracking Echocardiography From Birth to One Year of Life

Abstract

Introduction: Right ventricle (RV) systolic function is an important determinant of cardiopulmonary outcomes in premature infants. Two-dimensional speckle tracking echocardiography (2DSTE) derived myocardial strain is a reliable measure of RV systolic function in premature infants, but lacks reference values for clinical application in premature infants. We aimed to determine the maturational (age- and weight- related) changes in RV strain to establish reference values in preterm infants from birth to one year corrected age (CA). Methods: RV peak global longitudinal strain (pGLS) and RV free wall longitudinal strain (FWLS) were measured in a prospective longitudinal study in 115 preterm infants (< 29 weeks at birth) at 24 and 72 hours of age (HOA), 32 and 36 weeks postmenstrual age (PMA), and one year (CA) by 2DTSE (GE EchoPac) from a RV-focus apical 4-chamber view using a validated protocol. Premature infants that developed chronic lung disease or had a hemodynamically significant PDA were excluded (n=65) from analysis for the reference values. Results: RV pGLS ranged from -16% at birth to -26% by one year CA and RV FWLS ranged from -18% at birth to -27% to one year CA in healthy preterm infants. RV pGLS and FWLS strain correlated with increasing weight (r=0.87, p < 0.001), PMA in weeks (r=0.85, p < 0.001; r=0.83, p < 0.001), but were independent of gestational age at birth (r=0.4, p=0.38; r=0.3, p=0.5). RV strain was significantly lower in preterm infants with bronchopulmonary dysplasia (p=0.004) at 32 and 36 weeks PMA, and one year CA (Figure). RV strain was independent of gender or need for mechanical ventilation. Conclusions: This study establishes reference values of RV global and free wall longitudinal strain and tracks their postnatal maturational changes in preterm infants. These measures increase from birth to one year CA and are linearly associated with increasing weight reflecting the postnatal cardiac growth as a contributor to the maturation of RV function.