Feasibility, Reproducibility and Reference Ranges of Left Atrial Strain in Preterm and Term Neonates in the First 48 h of Life

Abstract

Left atrial strain (LAS) is the most promising technique for assessment of diastolic dysfunction but few data are available in neonates. Our aim was to assess feasibility and reproducibility, and to provide reference ranges of LAS in healthy neonates in the first 48 h of life. We performed one echocardiography in 30 neonates to assess feasibility and develop a standard protocol for image acquisition and analysis. LAS reservoir (LASr), conduit (LAScd) and contraction (LASct) were measured. We performed echocardiography at 24 and 48 h of life in an unrelated cohort of 90 neonates. Median (range) gestational age and weight of the first cohort were 34.4 (26.4–40.2) weeks and 2075 (660–3680) g. LAS feasibility was 96.7%. Mean (SD) gestational age and weight of the second cohort were 34.2 (3.8) weeks and 2162 (833) g. Mean (SD) LASr significantly increased from 24 to 48 h: 32.9 (3.2) to 36.8 (4.6). Mean (SD) LAScd and LASct were stable: −20.6 (8.0) and −20.8 (9.9), −11.6 (4.9) and −13.5 (6.4). Intra and interobserver intraclass correlation coefficient for LASr, LAScd and LASct were 0.992, 0.993, 0.986 and 0.936, 0.938 and 0.871, respectively. We showed high feasibility and reproducibility of LAS in neonates and provided reference ranges.

Global longitudinal strain is an informative index of left ventricular performance in neonates receiving intensive care

“…Three cardiac cycles were digitally stored at high frame rate (100–130 Hz). Image quality was assessed according to Colan et al 14 Images considered poor or unusable were excluded from the analysis 15 .…”

Tissue‐Tracking Mitral Annular Displacement in Neonates

“…Inclusion criteria were: informed parental consent and cardio‐respiratory healthiness. The latter was defined on the basis of clinical parameters: no need of supplemental oxygen and/or respiratory support, except for babies with a GA ≤32 weeks, in whom non‐invasive respiratory support with a FiO 2 <0.3 was accepted, as previously reported 17 . Exclusion criteria were: need for inotropes and/or vasopressors, suspected sepsis, major congenital abnormalities, congenital heart disease, except for PDA and patent foramen ovale (PFO), small or large for gestational age, intrauterine growth retardation, pulmonary hypertension, and infants of diabetic mother.…”

“…Three cardiac cycles were digitally stored in high frame rate (100–130 Hz). Image quality was assessed according to Colan et al 18,19 Images considered poor or unusable were excluded from the analysis 17 . Images were analyzed offline using QLAB 9.0, Philips Medical Systems.…”

“…To assess intraobserver and interobserver reproducibility, measurements of LV systolic function were repeated 4 weeks apart, to avoid recall bias, in a sub‐cohort of randomly chosen subjects by the same observer and by a second observer blinded to previous data 17 …”

“…To reach an 80% power at 0.05 level the sample size was 23 scans. Intraobserver and interobserver reproducibility were assessed using Bland–Altman analysis (mean bias and limits of agreement, LOA), intraclass correlation coefficient (ICC) with 95% CI, and coefficient of variation (COV) 17,19 . P value <.05 was considered significant.…”