Maturational Patterns of Systolic Ventricular Deformation Mechanics by Two-Dimensional Speckle-Tracking Echocardiography in Preterm Infants over the First Year of Age

Abstract

Background We aimed to determine the maturational changes in systolic ventricular strain mechanics by two-dimensional speckle tracking echocardiography in extreme preterm neonates from birth to one year of age, and discern the impact of common cardiopulmonary abnormalities on the deformation measures. Methods In a prospective multi-center study of 239 extreme preterm infants (< 29 weeks gestation at birth), left ventricle (LV) global longitudinal strain and systolic strain rate (GLS, GLSRs), interventricular septal wall (IVS) GLS and GLSRs, right ventricle free wall longitudinal S and SR (RV FWLS, FWLSRs), and segmental LS (SLS) in the RVFW, LVFW and IVS were serially measured at Days 1, 2, 5–7, 32 weeks and 36 weeks post-menstrual age (PMA), and one year corrected age (CA). Premature infants who developed bronchopulmonary dysplasia (BPD) or had echocardiographic findings of pulmonary hypertension (PH) were analyzed separately. Results In uncomplicated preterm infants (n=103, 48%), LV GLS and GLSRs remained unchanged from Day 5–7 to one year CA (p=0.60 and 0.59). RV FWLS, FWLSRs and IVS GLS and GLSR significantly increased over the same time period (p < 0.01 for all measures). A significant base-to-apex (highest to lowest) SLS gradient (p < 0.01) in the RVFW and a reverse apex-to-base gradient (p < 0.01) existed in the LVFW. In infants with BPD and/or PH (n=119, 51%), RV FWLS and IVS GLS were significantly lower (p < 0.01), LV GLS and GLSRs were similar (p=0.56), and IVS SLS persisted as an RV dominant base-to-apex gradient from 32 weeks PMA to one year CA. Conclusions This study tracks the maturational patterns of global and regional deformation by 2DSTE in extreme preterm infants from birth to one year CA. The maturational patterns are ventricular specific. BPD and PH leave a negative impact on RV and IVS strain, while LV strain remains stable.

Longitudinal evaluation of myocardial function in preterm infants with respiratory distress syndrome

“…Our finding is slightly different from those published by other groups where LV strain had remained stable from birth through to 28 days and 36 weeks post‐menstrual age . Levy et al used 2D speckle tracking method to assess LV global strain and reported an initial increase in LV strain in the first 7 days of life but thereafter the LV strain value stabilized until 1 year corrected age. One possible reason for this discrepancy between our finding and other published data could be to the timing of the assessments.…”

Circumferential and radial deformation assessment in premature infants: Ready for primetime?

“…This finding is consistent with reports assessing LV circumferential and radial strain at the level of the papillary muscle between day 1 and 2 months of age in a healthy term cohort, demonstrating no difference in these parameters during that time period . Interestingly, the persevered measures during the transitional phase are also consistent with the observed patterns of LV longitudinal strain patterns during the transitional period, early neonatal period, and through 1 year of age in premature infants …”

“…Longitudinal deformation parameters (strain, SRs, SRe, and SRa) were also obtained from the apical 4‐chamber view for reproducibility analysis to serve as a reference for comparison. Our group has previously published reference values and demonstrated excellent reproducibility for longitudinal deformation measurements in this population …”

“…As a result, LV deformation comprises radial thickening, circumferential shortening, and longitudinal shortening; myocardial strain describes this deformation under an applied force . LV longitudinal deformation remains the most reproducible quantitative tool of the three to assess LV function in preterm infants during the transitional period and later neonatal period . In addition, reference ranges for 2D STE‐derived LV longitudinal deformation parameters now exist, and their response to common preterm morbidities are also becoming available …”

A comparison between Philips and Tomtec for left ventricular deformation and volume measurements in neonatal intensive care patients

“…Longitudinal strain (S L ) is the most common deformation parameter used in clinical practice in adults. 2DSTE has also been successfully applied in neonatal research and has significantly increased our knowledge of functional cardiac development in preterm infants . Reliability of longitudinal strain (S L ) is superior compared to currently used conventional parameters, and reference values have been established in the term and preterm population .…”