221 - Extremely Preterm Infants with Bronchopulmonary Dysplasia and Late Systemic Hypertension Have Higher Stroke Work and Decreased Left Ventricular Longitudinal Strain

Poster Number: 221
Publication Number: 221.221

Melanie Reyes, University of Iowa Stead Family Children's hospital, Iowa City, IA, United States; Adrianne Rahde Bischoff, University of Iowa, Iowa city, IA, United States; Regan E. Giesinger, University of Iowa, Iowa City, IA, United States; Amy Stanford, University of Iowa Stead Family Children's Hospital, Iowa City, IA, United States; Danielle R. Rios, University of Iowa Stead Family Children's Hospital, Iowa City, IA, United States; Patrick J. McNamara, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA, United States

Background: Recent evidence suggests that the relationship between systemic hypertension (SH) and left ventricular (LV) diastolic performance in extremely preterm infants is an important determinant of lung disease in infants with “presumed” bronchopulmonary dysplasia (BPD). Echocardiography-derived estimates of Ventriculo-Arterial coupling (VAC) and strain can be used to understand the interactions between the immature LV and the load of the arterial system.

Objective: To assess Ventriculo-Arterial coupling parameters in extremely preterm infants with BPD and late onset systemic hypertension versus normotension

Design/Methods: Serial targeted neonatal echocardiography (TnECHO) evaluation is routinely performed in premature infants with a diagnosis of BPD, born < 28 weeks gestational age (GA), beginning at either 8 postnatal weeks or 34 weeks corrected GA. All infants who underwent routine screening (09/2018-11/2019) were reviewed and a single TnECHO ( >34 weeks GA) with the most pathologic features of pulmonary vascular disease was selected. Cases were categorized, based on systolic arterial pressure (SAP) at the time of the TnECHO, as systemic hypertension [SH, SAP >90mmHg] or normotension [NT, SAP < 90mmHg]. Comprehensive TnECHO analyses were performed by a single operator, blinded to group allocation. Markers of VAC, including LV end-systolic elastance (Ees) and arterial elastance (Ea) were assessed. Figure 1A depicts the pressure-volume loop. LV and left atrium (LA) size and volumes were estimated. 2D-speckle tracking Echo was used to measure longitudinal deformation of the LV and LA. LV ejection time (LVETc) and systemic vascular resistance index (SVRi = LVET/ Aortic acceleration time) were estimated from the LV outflow tract Doppler tracing.

Results: A total of 64 infants were included, 47% with SH. Baseline demographics, neonatal morbidities and degree of respiratory support were comparable between groups (Table 1). SH infants had higher Ea and Ees (Table 2), with a bigger area under the PV loop curve (Figure 1B). VAC and VE were similar between the groups. Although there were no differences in left heart size or volume, infants with SH had lower systolic LA and LV strain rates.Conclusion(s): Extremely preterm infants with BPD and SH have higher Ea and Ees with decreased LV and LA systolic strain rates. The differences in Ea and Ees represent higher stroke work and myocardial oxygen consumption in infants with SH. The modulator effects of anti-hypertensive medications and life-long ramifications of this abnormal vasculo-ventricular phenotype remains unknown.
Table 1: Demographics and maternal characteristics of infants with systemic hypertension (SH) and normotension (NT)TnECHO: targeted neonatal echocardiography; SAP, systolic arterial pressure; DAP, diastolic arterial pressure; PEEP: positive end expiratory pressure; CPAP: continuous positive airway pressure. Results presented in frequency (%), mean±SD, median [IQR].
Table 2: Targeted Neonatal Echocardiography indices of infants with systemic hypertension (SH) and normotension (NT)Ch, chamber; LA, Left Atrium; LV, Left Ventricle; LVETc, Left Ventricular Ejection Time corrected to heart rate; SVRi, Systemic Vascular Resistance Index; Ea, Arterial elastance; Ees, End-Systolic elastance; VAC, Ventriculo-arterial coupling; VE, ventricular efficiency. Results presented in frequency (%), mean±SD, median [IQR].