Myocardial performance assessment in neonates by one-segment strain and strain rate analysis by tissue Doppler - a quality improvement cohort study

Abstract

ObjectivesTo investigate one-segment strain and strain rate indices as measures of myocardial performance in asphyxiated term neonates.DesignQuality improvement cohort study.SettingNewborns admitted to a neonatal intensive care unit at a Norwegian University Hospital for perinatal asphyxia and non-asphyxiated newborn recruited from the maternity ward at the same hospital.ParticipantsTwenty asphyxiated and 48 non-asphyxiated term neonates.Primary outcome measureStrain and strain rate indices and repeatability measures. One-segment longitudinal strain and strain rate by tissue Doppler were assessed on days 1, 2 and 3 of life in nine heart walls. Repeatability was compared against measurements from two-segment analyses previously performed in the same images.ResultsThe 95% limits of agreement were significantly better for the one-segment than two-segment repeatability analyses, the inter-rater peak systolic strain (PSS) was (−3.1, 3.3) vs (−11.4, 18.3)%, the inter-rater peak systolic strain rate (PSSR) was (−0.38, 0.40) vs (−0.79, 1.15)/s, the intra-rater PSS was (−2.5, 2.6) vs (−8.0, 9.8)% and the intra-rater PSSR was (−0.23, 0.25) vs (−0.75, 0.80)/s (p<0.05). The myocardial performance was lower in the asphyxiated neonates (indices closer to zero) than in the non-asphyxiated neonates, PSS was −17.8 (0.6) (mean (SEM)) vs −21.2 (0.3)%, PSSR −1.43 (0.08) vs −1.61 (0.03)/s, early diastolic strain rate 1.72 (0.11) vs 2.00 (0.11)/s and strain rate during the atrial systole 1.92 (0.17) vs 2.27 (0.10)/s (p<0.05), despite no difference in fractional shortening (29.0 (0.5) vs 29.1 (1.0)%) (p>0.05).ConclusionsOne-segment strain and strain rate assessed the reduced myocardial performance in asphyxiated neonates with significantly improved reproducibility as compared with two-segment analysis and was therefore more feasible than two-segment analyses for assessment of myocardial performance after perinatal asphyxia.

Deformation imaging and rotational mechanics in neonates: a guide to image acquisition, measurement, interpretation, and reference values

“…Nestaas et al demonstrated that LV and RV deformation parameters are uniformly lower in infants with hypoxic ischemic encephalopathy (HIE) compared with healthy controls. 35 Interestingly, these differences occurred while SF was preserved between groups, further demonstrating that strain imaging permits a more comprehensive assessment of myocardial performance in neonates that could not be previously obtained with conventional imaging. 35 The same group of investigators also demonstrated that infants with HIE have similarly impaired myocardial function during days 1–3, irrespective of whether they received therapeutic hypothermia, suggesting that myocardial injury may be a result of the initial insult rather than “cooling” treatment.…”

“… 11 , 36 , 37 , 41 The most reproducible measurements are assessed in longer segments and when the LV base free wall is avoided as site of measurement. 35 Nestaas et al conducted the first studies of reproducibility in term infants and revealed moderate reproducibility in obtaining strain and systolic SR with intraclass correlation coefficients (ICC) ranging between 0.6–0.7 for intra-observer and 0.4–0.5 for inter-observer repeated measures. 36 , 43 With enhanced image optimization techniques, reliability data have improved in term neonates for basal strain with coefficients of variation (COV) values <15% and ICC values >0.75.…”

“… 36 , 43 With enhanced image optimization techniques, reliability data have improved in term neonates for basal strain with coefficients of variation (COV) values <15% and ICC values >0.75. 35 , 38 , 40 In preterm infants, measurements are feasible in about 90% of studies when adequate imaging quality is achieved. 41 Poon et al reported COV values of <5% for LV, septal and RV basal strain in preterm infants.…”

“…Optimal probe choices, ideal ROI width and length and SL lengths have been published for term and preterm infants and are summarized in Table 1 . 35 , 36 , 38 , 39 , 43

Fig. 6 Offline measurement of SR and strain using tissue Doppler.

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“…Reference ranges for deformation parameters exist in the term and preterm neonates 26 , 35 , 37 , 45 (Table 2 ). In the term population, LV longitudinal strain values range between −20 and −25 (%), while SRs values range between −1.5 and −2.5 1/s, SRe between 2.8 and 3.2 1/s, and SRa slightly lower between 2.1 and 2.4 1/s.…”