245 - Validity of Targeted Neonatal Echocardiography for Ventricular Size and Function in Premature Neonates with Chronic Pulmonary Hypertension: Comparison with Cardiac MRI

Poster Number: 245
Publication Number: 245.222

Amish Jain, University of Toronto/ Mount Sinai Hospital, Toronto, ON, Canada; Andrea Pisesky, The Hospital for Sick Children, Toronto, ON, Canada; Dany E. Weisz, University of Toronto, Toronto, ON, Canada; Luc Mertens, University of Toronto Temerty Faculty of Medicine, Toronto, ON, Canada; Patrick J. McNamara, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA, United States; Mike Seed, University of Toronto Temerty Faculty of Medicine, Toronto, ON, Canada

Background: Chronic pulmonary hypertension (cPH) in premature neonates is commonly monitored using targeted neonatal echocardiography (TNE) in neonatal intensive care units (NICUs). While many TNE indices of right (RV) and left (LV) ventricular size and function are commonly used in clinical and research settings, their relative validity is not well established.

Objective: To examine the validity of TNE indices of RV and LV size and function in preterm neonates with cPH by comparing with cardiac MRI.

Design/Methods: Sixteen preterm neonates with chronic lung disease and known diagnosis of cPH, defined as flat interventricular septum at end-systole and RV dilation on echocardiography at ≥ 36 weeks postmenstrual age (PMA), were prospectively recruited at a tertiary NICU and underwent comprehensive TNE evaluations and cardiac-MRIs, performed using feed and sleep method, on the same day. Images were obtained for relevant measures of RV and LV size, function and outputs. MRIs and TNEs were independently analyzed by separate blinded personnel. MRI end-diastolic volumes (EDV) and ejection fractions (EF) were compared to TNE indices of RV/LV size and systolic function, respectively. Phase contrast MRI (PC-MRI) derived flow in main pulmonary artery, ascending aorta and pulmonary: systemic flow (Qp:Qs) were compared with TNE RV output (RVO), LVO, and their ratio, respectively. Correlation between MRI and TNE indices were examined by Pearson correlation coefficient and agreement by Bland-Altman analysis, if relevant.

Results: Fifteen of 16 infants were receiving diuretics for RV congestion and 13 were on respiratory support at evaluation (table 1). TNE measures of RV and LV dimensions correlated well with MRI-EDV; however, only RV fractional area change (3-chamber view) and LVEF (Teichholz formula) correlated with respective MRI-EF (Tables 2, 3). TNE-derived RV and LV outputs and their ratio correlated with respective flows and Qp:Qs on PC-MRI. There was, however, poor agreement between methods with TNE values lower than MRI for most measures.Conclusion(s): This study suggests that simple bedside TNE measures may be valid for monitoring changes in ventricular size, flow and Qp:Qs in preterm neonates with cPH. TNE and MRI do not correlate for the majority of functional indices, indicating the need for further validation, preferably against clinical outcomes.
Table 1Cohort description
Table 2Right ventricular size and function MRI vs. TNE