P744Analysis of peak systolic longitudinal strain and strain rate by tissue Doppler in neonates is simplified and improved by use of one-segment analysis and stationary sample area


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Abstract

Purpose: Strain and strain rate are size-independent indices of myocardial deformation, especially well suited for myocardial evaluation during growth. The reduced myocardial deformation in birth asphyxia has been shown by two-segment peak systolic longitudinal strain (PSS) and strain rate (PSSR) by tissue Doppler using tracked region-of-interest (ROI). However, the analysis procedure is time consuming and the variability in the repeatability analyses is high. Segmental analysis based on the coronary blood supply is less relevant in neonates. Hence, one large segment from each wall and stationary ROIs can be used, simplifying the analysis procedure and possibly reducing the variability. This study compares a simplified one-segment analysis procedure using stationary ROIs in healthy and asphyxiated term neonates against the two-segment analysis procedure using tracked ROI.Methods: Tissue Doppler images from four left heart walls, two septum walls and three right heart walls were obtained in healthy and asphyxiated term neonates on day 1, 2 and 3 of life. One-segment longitudinal PSS and PSSR obtained by stationary ROIs were assessed and were compared against similar two-segment values obtained by tracked ROIs. Mean values and repeatability measurements were compared. The fractional shortening (%FS) was assessed at each examination.Results: 138 examinations from 48 healthy and 53 examinations from 20 asphyxiated term neonates were analysed. The mean one-segment PSS and PSSR were lower (closer to zero) in the asphyxiated neonates (PSS -17.8% (0.6) (mean (SEM)), PSSR –1.42/s (0.04)) than in the healthy term neonates (PSS -21.2% (0.5), PSSR -1.61/s (0.03)), p<0.05). The %FS was similar in the asphyxiated (29.1% (1.04)) and healthy term neonates (29.0% (0.53), p=0.92). The variations in the repeatability analyses were lower in the one-segment analyses (p<0.05). The one-segment values were lower than the corresponding two-segment values (asphyxiated neonates PSS -19.4% (0.5) and PSSR -1.65/s (0.04), healthy neonates PSS -21.7% (0.3) and PSSR -1.78/s (0.03)), p<0.05).Conclusions: One-segment peak systolic longitudinal strain and strain rate can be used for assessing the reduced myocardial deformation in birth asphyxia, and were more sensitive indices than %FS for assessing the impaired myocardial function in asphyxiated term neonates. The variations in the repeatability analyses were lower in the one-segment analyses than in the two-segment analyses. The one-segment values were lower than the corresponding two-segment values, both in the healthy and the asphyxiated neonates.

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