257 - Fractional Area Change as an Index of Left Ventricular Systolic Function in Preterm Infants

Publication Number: 4253.257

Erin D. Myers, Keck School of Medicine of the University of Southern California, Los angeles, CA, United States; Mahmood Ebrahimi, Cedars Sinai Medical Center, Encino, CA, United States; Shahab Noori, Children’s Hospital Los Angeles, Los Angeles, CA, United States

Background: Shortening fraction (SF) is the most commonly used index of left ventricular (LV) systolic function. However, as it only represents changes in LV dimension in cross-section along a single line, it has significant limitations in assessing systolic function. Fractional area change (FAC), measures the changes in LV cross-sectional area in systole and diastole and therefore may better represent LV systolic function than SF. There is limited information on FAC in neonates, especially in preterm infants.

Objective: To describe FAC values among hemodynamically stable preterm infants less than 30 weeks gestation in the first postnatal week, and to investigate if FAC is a superior metric compared with SF to evaluate LV systolic function.

Design/Methods: IRB approval was obtained for this retrospective cohort study of infants between 22 to 29 weeks gestation who had echocardiograms completed within the first postnatal week. Echocardiograms were reviewed by a single individual, and measurements for SF, FAC, and left ventricular output (LVO) were recorded. FAC was obtained via 2D short axis view area measurements in systole and diastole, and calculated as FAC = [(end diastolic area - end systolic area)/end diastolic area) x 100]. Pearson and Spearman correlations were used depending on normality of distribution (Shapiro-Wilk Test). Univariate regression was used to evaluate association between LVO and SF as well as LVO and FAS.

Results: A total of 76 preterm infants, born at 25.4 ± 1.8 weeks with median birthweight 747 grams (IQR 625-940) and had an echocardiogram on day of life 3 ± 1.9 were included. Table 1 and 2 show FAC and SF, respectively, for different gestational age groups. There was good correlation between SF and FAC (r=0.55, p< 0.0001). SF and FAC had no correlations with birth weight or gestational age. Using univariate regression, there was no association between LVO and SF or FAC.

Conclusion(s): We delineate FAC values as an index of LV systolic function in the preterm infant population. In our hemodynamically stable population, neither SF nor FAC was predictive of LVO. Further research is needed to investigate the potential utility of FAC in hemodynamically unstable populations and in patients with interventricular septal flattening or myocardial dyskinesis.

Table 1: Fractional Area Change in Preterm Infants 22-29 Weeks Gestation
FAC was obtained via 2D short axis view area measurements in systole and diastole, and calculated as FAC = [(end diastolic area - end systolic area)/end diastolic area) x 100]. FAC had no correlation with birth weight or gestational age.

Table 2: Shortening Fraction in Preterm Infants 22-29 Weeks Gestation
SF had no correlation with birth weight or gestational age.