Myocardial performance index (Tei index) in term and preterm neonates during the neonatal period

Abstract

A b s t r a c t Background:The myocardial performance index (MPI) is a noninvasive method to measure global systolic and diastolic myocardial function. In both term and premature neonates, changes in the systolic and diastolic function of the left ventricle (LV) and right ventricle (RV) reflect the degree of neonatal myocardial immaturity and the co-existence of foetal circulation. Aim:To assess MPI (or Tei indices) of both ventricles in term and preterm newborns, and to observe MPI trends throughout the neonatal period. Methods:Heart ultrasound imaging was performed on the first day of life (DOL), after patent ductus arteriosus (PDA) closure, and on the 28 th DOL, in 29 term and 29 preterm newborns. RVMPI and LVMPI were measured within the preterm group at 40 weeks of post-conception age (PCA).Results: A statistically significant reduction in RVMPI was observed in both term and preterm newborns. In term newborns, the RVMPI value on the first DOL was 0.42 ± 14, dropping to 0.29 ± 0.09 after PDA closure, and finally reaching 0.22 ± 0.09 on the 28 th DOL. The respective RVMPI values for the preterm newborns were 0.44 ± 0.15, 0.30 ± 0.12, and 0.21 ± 0.08. Little variability in the mean values of LVMPI was observed in both groups throughout the neonatal period. The LVMPI for term neonates in successive measurements was 0.37 ± 0.10, 0.39 ± 0.07, and 0.37 ± 0.11, respectively, and for the preterm neonates it was 0.37 ± 0.10, 0.35 ± 0.09, and 0.36 ± 0.10, respectively. The MPI values from preterm newborns taken at 40 weeks PCA (RVMPI = 0.28 ± 0.09; LVMPI = 0.37 ± 0.05) were comparable to those measured in term newborns after PDA closure. Conclusions:Observed postnatal changes in RVMPI correspond to changes in ventricular function, reflecting the haemodynamic changes of the transitional circulation. The relatively small postnatal changes in LVMPI in term and preterm newborns may reflect an immature myocardium. The RVMPI and LVMPI values at 40 weeks PCA in preterm newborns correlate best with MPI values in term newborns just after PDA closure.

Echocardiographic analysis of left ventricular function in term and preterm neonates at week 40 of postconceptional life

“…18 In our study, echocardiography was the only technique to assess myocardial function because other methods, particularly invasive measurements, cannot be used in neonates due to high risk. However, the strength of our study is a large group of preterm neonates (n = 89) compared with previous studies involving much smaller groups (n = 16-29), 14,17 which compensates for the lack of invasive measurements.…”

Cardiac left heart morphology and function in newborns with intrauterine growth restriction: relevance for long-term assessment

“…The EF may be a better tool but it is closely influenced by the ventricular preload [15]. The myocardial performance index has been proposed as a parameter in the assessment of systolic and diastolic performance but it can be influenced by preload and afterload [16]. Normal values of MPI for healthy term newborns range from 0.25 to 0.38 but few studies assess its reproducibility [17].…”

Ecocardiografía Funcional y sus aplicaciones clínicas en Neonatología

“…La función sistólica del VI es evaluada con la fracción de acortamiento (FA) y la fracción de eyección (FE). La FA es la más usada y reproducible siendo su valor normal 25%-40%, pero varios estudios han demostrado su baja sensibilidad ya que se ve afectada por la precarga, postcarga y deformidades del tabique [23][24][25] . La FE es una evaluación volumétrica del acortamiento de la fibra ventricular, el mejor método de medición es la planimetría usando el método de Simpson modificado.…”

“…Existen valores normales definidos según edad gestacional y días de vida 5 . El índice Tei o de performance miocárdica permite evaluar la función sistólica y diastólica en forma simultánea, medido con DT a nivel del anillo lateral de la mitral, entrega información de la contractilidad del VI (valores normales = 0,35 ± 0,03) 18,24,25 . Diferentes estudios en recién nacidos que cursan condiciones patológicas han mostrado alteraciones en las mediciones del DT más precoces que las mediciones tradicionales de función miocárdica 25 .…”